The Experts below are selected from a list of 612 Experts worldwide ranked by ideXlab platform

Toshifumi Takenaka - One of the best experts on this subject based on the ideXlab platform.

  • fatty acids as an energy source for the operation of Axoplasmic Transport
    Brain Research, 2003
    Co-Authors: Toshifumi Takenaka, Hideaki Hori, Yoko Hashimoto, Hiromi Hiruma, Takafumi Ichikawa, Tadashi Kawakami
    Abstract:

    Fatty acids are utilized as a cellular energy source. In the present study, we investigated whether fatty acids could affect Axoplasmic Transport. Cultured mouse superior cervical ganglion neurons were placed in the glucose-containing medium (145 mM NaCl, 5 mM KCl, 1 mM CaCl(2), 1 mM MgCl(2), 5 mM D-glucose, 10 mM Hepes, pH 7.3, 37 degrees C), and Axoplasmic Transport of particles in neurites was observed under video-enhanced contrast microscopy. A variety of fatty acids (acetate (C2), caproate (C6), caprylate (C8), caprate (C10), 2-decenoate (C10:1), arachidonate (C20:4); 0.1-1 mM) caused a transient increase in the amount of particles Transported in both anterograde and retrograde directions. The increasing effects of fatty acids were dose-dependent. A half-maximum effective dose (ED(50)) for acetate was 0.8 mM, which is similar to the reported K(m) value of acetyl-CoA synthetase for acetate. The ED(50) for caprylate was 28 microM, which is near the K(m) value of acyl-CoA synthetase for medium- and long-chain fatty acids. Application of 5 mM malonate, an inhibitor of the citrate cycle, induced a steady-state decrease in Axoplasmic Transport, indicating that energy derived from the citrate cycle is required for the maintenance of Axoplasmic Transport. The increasing effect of acetate (1 mM) on Axoplasmic Transport was completely abolished by pretreatment with malonate (5 mM), suggesting that acetate produces ATP for Axoplasmic Transport via the citrate cycle. Alternatively, the effect of caprate (1 mM) was retained after treatment with malonate. Thus, fatty acids except acetate produce ATP probably through both the beta-oxidation pathway and the citrate cycle, increasing Axoplasmic Transport. Since the effect of fatty acids was transient, certain negative feedback mechanisms might be involved. The removal of glucose from the medium resulted in a low steady-state level of Axoplasmic Transport. Under such condition, the acetate (1 mM)-induced transient increase in Axoplasmic Transport remained. Since intracellular ATP must be low under glucose-free condition, intracellular ATP concentrations are unlikely to be involved in the feedback system. Instead, acetyl-CoA or its downstream products in the citrate cycle might lead to feedback inhibition. Application of citrate (5 mM) caused a strong decrease following a transient increase in Axoplasmic Transport, whereas no other acetyl-CoA product decreased Axoplasmic Transport. Thus, excessive citrate may be one of factors leading to feedback inhibition of metabolic pathways to arrest and reverse the increase in Axoplasmic Transport induced by fatty acids.

  • growth cone neuropilin 1 mediates collapsin 1 sema iii facilitation of antero and retrograde Axoplasmic Transport
    Journal of Neurobiology, 1999
    Co-Authors: Yoshio Goshima, Toshifumi Takenaka, Hideaki Hori, Yukio Sasaki, Tao Yang, Masako Kagoshimamaezono, Fumio Nakamura, Takuya Takahashi, Stephen M Strittmatter, Yoshimi Misu
    Abstract:

    Collapsin-1/Sema III, a member of the semaphorin family, has been implicated in axonal pathfinding as a repulsive guidance cue. Cellular and molecular mechanisms by which collapsin-1 exerts its action are not fully understood. Collapsin-1 induces growth cone collapse via a pathway which may include neuropilin-1, a cellsurface collapsin-1 binding protein, as well as intracellular CRMP-62 and heterotrimeric G proteins. We previously identified a second action of collapsin-1, the facilitation of antero- and retrograde Axoplasmic Transport. This response occurs via a mechanism distinct from that causing growth cone collapse. To investigate the possible involvement of neuropilin-1 in the action of collapsin-1 on Axoplasmic Transport, we produced a soluble neuropilin-1 (sNP-1) lacking the transmembrane and intracellular region. sNP-1 progressively displaced the dose-response curve for collapsin-1 to induce growth cone collapse to higher concentrations. sNP-1 also inhibited collapsin-1-induced augmentation of both antero- and retrograde Axoplasmic Transport. Furthermore, an anti-neuropilin-1 antibody blocked the collapsin-induced Axoplasmic Transport. These results together indicate that neuropilin-1 mediates collapsin-1 action on Axoplasmic Transport. To visualize collapsin-1 binding to endogenous neuropilin-1, we used a truncated collapsin-1-alkaline phosphatase fusion protein (CAP-4). CAP-4 stains the growth cone, neurite, and cell body. However, local application of collapsin-1 to growth cone but to neither neurite nor cell body promotes Axoplasmic Transport. Thus, growth cone NP-1 mediates the facilitatory action of collapsin-1 on antero- and retrograde Axoplasmic Transport.

  • effects of alcar on the fast Axoplasmic Transport in cultured sensory neurons of streptozotocin induced diabetic rats
    Neuroscience Research, 1999
    Co-Authors: Masato Kano, Tadashi Kawakami, Hideaki Hori, Yoko Hashimoto, Yang Tao, Yoshihiro Ishikawa, Toshifumi Takenaka
    Abstract:

    The effects of acetyl-L-carnitine (ALCAR) on fast Axoplasmic Transport were studied in cultured dorsal root ganglion (DRG) neurons of diabetic rats. Three-month-old male rats were used 7 days after streptozotocin injection. Neurons obtained from ganglia were cultured with a high concentration of glucose. The amount and the mean velocity of retrogradely Transported particles, reduced in the diabetic animal, were transiently recovered by 1 mM ALCAR. The number of particles moving at 0.8-1.2 microm/s, considered to be lysosomes, increased in the velocity distribution. ALCAR did not modify the amount and mean velocity of anterograde particles which were unaffected by diabetes, or of bidirectional particles in neurons of control rats. This study suggests that diabetic neuropathy may be relieved by ALCAR via recovering retrograde Axoplasmic Transport.

  • Axoplasmic Transport and its signal transduction mechanism
    Journal of Physiological Sciences, 1998
    Co-Authors: Toshifumi Takenaka, Tadashi Kawakami, Hideaki Hori, Yoko Hashimoto, Hiromi Hiruma, Tatsumi Kusakabe
    Abstract:

    Neuron requires a continual supply of materials synthesized in the cell body, for example a wide range of soluble proteins, membranous components, and various organelles. The Transported materials are needed to replace constituents that turn over in the membrane and organelles of the fiber and also are needed to bring substances participating in energy metabolism. Other Transported components are neurotransmitters or transmitter-related components supplied to the nerve terminals for the release and subsequent excitation of postsynaptic cells. Moreover, neurotropic substances and modulators are released from the nerve terminals to affect the functional state of the neuron. Conversely, some materials are conveyed back to the cell body. These include organelles, lysosomes, nerve growth factor, and selected small molecules such as adenosine, Ca2+, and some neurotransmitters. Axoplasmic Transport is thought to be fundamental for a variety of neuronal cell functions. Thus it may be considered that Axoplasmic Transport relates to the dynamic physiological activity of neurons; in other words, Axoplasmic Transport is supposed to express the physiological activity of neurons. In turn, as in the case for many other physiological functions, Axoplasmic Transport is possibly controlled by neuronal, hormonal, and immunological systems. Since Axoplasmic Transport supplies neuron materials toward the synapses and back to the cell body, a feedback system of regulatory mechanisms of a variety of neuronal functions might be operated through Axoplasmic Transport pathways. Although Axoplasmic Transport is the important neuronal function, its regulation is poorly understood. In this review, we focus on the dynamics of organelle Transport and its regulatory mechanisms mediated by neurotransmitters.

  • a novel action of collapsin collapsin 1 increases antero and retrograde Axoplasmic Transport independently of growth cone collapse
    Journal of Neurobiology, 1997
    Co-Authors: Yoshio Goshima, Toshifumi Takenaka, Tadashi Kawakami, Hideaki Hori, Yoko Hashimoto, Masako Kagoshimamaezono, Yoshimi Misu, Yoshinobu Sugiyama, Shuichi Takasawa, Stephen M Strittmatter
    Abstract:

    Chick collapsin-1, a member of the by a mechanism distinct from that causing growth semaphorin family, has been implicated in axonal cone collapse. Pertussis toxin (PTX) but not its B pathfinding as a repulsive guidance cue. Collapsin-1 induces growth cone collapse via a pathway which oligomer blocks collapsin-induced growth cone col- may include CRMP-62 and heterotrimeric G proteins. lapse. The holotoxin does not affect collapsin-stimu- CRMP-62 protein is related to UNC-33, a nematode lated Axoplasmic Transport. Mastoparan and a myelin neuronal protein required for appropriately directed protein NI-35 induce PTX-sensitive growth cone col- axonal extension. Mutations in unc-33 affect neural lapse but do not stimulate Axoplasmic Transport. microtubules, the basic cytoskeletal elements for axo- These results provide evidence that collapsin has a plasmic Transport. Using computer-assisted video-en- unique property to activate axonal vesicular Transport hanced differential interference contrast microscopy, systems. There are at least two distinct pathways we now demonstrate that collapsin-1 potently pro- through which collapsin exerts its actions in motes Axoplasmic Transport. Collapsin-1 doubles the developing neurons. q 1997 John Wiley & Sons, Inc. J number of antero- and retrograde-Transported organ- Neurobiol 33: 316-328, 1997 elles but not their velocity. Collapsin-1 decreases the Keywords: collapsin; Axoplasmic Transport; nerve number of stationary organelles, suggesting that the growth cone; pertussis toxin; G proteins fraction of time during which a particle is moving is

Tadashi Kawakami - One of the best experts on this subject based on the ideXlab platform.

  • fatty acids as an energy source for the operation of Axoplasmic Transport
    Brain Research, 2003
    Co-Authors: Toshifumi Takenaka, Hideaki Hori, Yoko Hashimoto, Hiromi Hiruma, Takafumi Ichikawa, Tadashi Kawakami
    Abstract:

    Fatty acids are utilized as a cellular energy source. In the present study, we investigated whether fatty acids could affect Axoplasmic Transport. Cultured mouse superior cervical ganglion neurons were placed in the glucose-containing medium (145 mM NaCl, 5 mM KCl, 1 mM CaCl(2), 1 mM MgCl(2), 5 mM D-glucose, 10 mM Hepes, pH 7.3, 37 degrees C), and Axoplasmic Transport of particles in neurites was observed under video-enhanced contrast microscopy. A variety of fatty acids (acetate (C2), caproate (C6), caprylate (C8), caprate (C10), 2-decenoate (C10:1), arachidonate (C20:4); 0.1-1 mM) caused a transient increase in the amount of particles Transported in both anterograde and retrograde directions. The increasing effects of fatty acids were dose-dependent. A half-maximum effective dose (ED(50)) for acetate was 0.8 mM, which is similar to the reported K(m) value of acetyl-CoA synthetase for acetate. The ED(50) for caprylate was 28 microM, which is near the K(m) value of acyl-CoA synthetase for medium- and long-chain fatty acids. Application of 5 mM malonate, an inhibitor of the citrate cycle, induced a steady-state decrease in Axoplasmic Transport, indicating that energy derived from the citrate cycle is required for the maintenance of Axoplasmic Transport. The increasing effect of acetate (1 mM) on Axoplasmic Transport was completely abolished by pretreatment with malonate (5 mM), suggesting that acetate produces ATP for Axoplasmic Transport via the citrate cycle. Alternatively, the effect of caprate (1 mM) was retained after treatment with malonate. Thus, fatty acids except acetate produce ATP probably through both the beta-oxidation pathway and the citrate cycle, increasing Axoplasmic Transport. Since the effect of fatty acids was transient, certain negative feedback mechanisms might be involved. The removal of glucose from the medium resulted in a low steady-state level of Axoplasmic Transport. Under such condition, the acetate (1 mM)-induced transient increase in Axoplasmic Transport remained. Since intracellular ATP must be low under glucose-free condition, intracellular ATP concentrations are unlikely to be involved in the feedback system. Instead, acetyl-CoA or its downstream products in the citrate cycle might lead to feedback inhibition. Application of citrate (5 mM) caused a strong decrease following a transient increase in Axoplasmic Transport, whereas no other acetyl-CoA product decreased Axoplasmic Transport. Thus, excessive citrate may be one of factors leading to feedback inhibition of metabolic pathways to arrest and reverse the increase in Axoplasmic Transport induced by fatty acids.

  • effects of alcar on the fast Axoplasmic Transport in cultured sensory neurons of streptozotocin induced diabetic rats
    Neuroscience Research, 1999
    Co-Authors: Masato Kano, Tadashi Kawakami, Hideaki Hori, Yoko Hashimoto, Yang Tao, Yoshihiro Ishikawa, Toshifumi Takenaka
    Abstract:

    The effects of acetyl-L-carnitine (ALCAR) on fast Axoplasmic Transport were studied in cultured dorsal root ganglion (DRG) neurons of diabetic rats. Three-month-old male rats were used 7 days after streptozotocin injection. Neurons obtained from ganglia were cultured with a high concentration of glucose. The amount and the mean velocity of retrogradely Transported particles, reduced in the diabetic animal, were transiently recovered by 1 mM ALCAR. The number of particles moving at 0.8-1.2 microm/s, considered to be lysosomes, increased in the velocity distribution. ALCAR did not modify the amount and mean velocity of anterograde particles which were unaffected by diabetes, or of bidirectional particles in neurons of control rats. This study suggests that diabetic neuropathy may be relieved by ALCAR via recovering retrograde Axoplasmic Transport.

  • Axoplasmic Transport and its signal transduction mechanism
    Journal of Physiological Sciences, 1998
    Co-Authors: Toshifumi Takenaka, Tadashi Kawakami, Hideaki Hori, Yoko Hashimoto, Hiromi Hiruma, Tatsumi Kusakabe
    Abstract:

    Neuron requires a continual supply of materials synthesized in the cell body, for example a wide range of soluble proteins, membranous components, and various organelles. The Transported materials are needed to replace constituents that turn over in the membrane and organelles of the fiber and also are needed to bring substances participating in energy metabolism. Other Transported components are neurotransmitters or transmitter-related components supplied to the nerve terminals for the release and subsequent excitation of postsynaptic cells. Moreover, neurotropic substances and modulators are released from the nerve terminals to affect the functional state of the neuron. Conversely, some materials are conveyed back to the cell body. These include organelles, lysosomes, nerve growth factor, and selected small molecules such as adenosine, Ca2+, and some neurotransmitters. Axoplasmic Transport is thought to be fundamental for a variety of neuronal cell functions. Thus it may be considered that Axoplasmic Transport relates to the dynamic physiological activity of neurons; in other words, Axoplasmic Transport is supposed to express the physiological activity of neurons. In turn, as in the case for many other physiological functions, Axoplasmic Transport is possibly controlled by neuronal, hormonal, and immunological systems. Since Axoplasmic Transport supplies neuron materials toward the synapses and back to the cell body, a feedback system of regulatory mechanisms of a variety of neuronal functions might be operated through Axoplasmic Transport pathways. Although Axoplasmic Transport is the important neuronal function, its regulation is poorly understood. In this review, we focus on the dynamics of organelle Transport and its regulatory mechanisms mediated by neurotransmitters.

  • a novel action of collapsin collapsin 1 increases antero and retrograde Axoplasmic Transport independently of growth cone collapse
    Journal of Neurobiology, 1997
    Co-Authors: Yoshio Goshima, Toshifumi Takenaka, Tadashi Kawakami, Hideaki Hori, Yoko Hashimoto, Masako Kagoshimamaezono, Yoshimi Misu, Yoshinobu Sugiyama, Shuichi Takasawa, Stephen M Strittmatter
    Abstract:

    Chick collapsin-1, a member of the by a mechanism distinct from that causing growth semaphorin family, has been implicated in axonal cone collapse. Pertussis toxin (PTX) but not its B pathfinding as a repulsive guidance cue. Collapsin-1 induces growth cone collapse via a pathway which oligomer blocks collapsin-induced growth cone col- may include CRMP-62 and heterotrimeric G proteins. lapse. The holotoxin does not affect collapsin-stimu- CRMP-62 protein is related to UNC-33, a nematode lated Axoplasmic Transport. Mastoparan and a myelin neuronal protein required for appropriately directed protein NI-35 induce PTX-sensitive growth cone col- axonal extension. Mutations in unc-33 affect neural lapse but do not stimulate Axoplasmic Transport. microtubules, the basic cytoskeletal elements for axo- These results provide evidence that collapsin has a plasmic Transport. Using computer-assisted video-en- unique property to activate axonal vesicular Transport hanced differential interference contrast microscopy, systems. There are at least two distinct pathways we now demonstrate that collapsin-1 potently pro- through which collapsin exerts its actions in motes Axoplasmic Transport. Collapsin-1 doubles the developing neurons. q 1997 John Wiley & Sons, Inc. J number of antero- and retrograde-Transported organ- Neurobiol 33: 316-328, 1997 elles but not their velocity. Collapsin-1 decreases the Keywords: collapsin; Axoplasmic Transport; nerve number of stationary organelles, suggesting that the growth cone; pertussis toxin; G proteins fraction of time during which a particle is moving is

  • Signal transduction mechanism responsible for changes in Axoplasmic Transport caused by neurotransmitters.
    Neurochemical research, 1996
    Co-Authors: Toshifumi Takenaka, Tadashi Kawakami
    Abstract:

    Transduction mechanism for modulation of Axoplasmic Transport by neurotransmitters was studied using cultured mouse superior cervical ganglion cells. The Transported particles were analyzed with a computer-assisted video-enhanced differential interference contrast microscope system. Acetylcholine depressed and adrenaline increased Axoplasmic Transport. GTP-binding proteins linked with both receptors activate or inactivate adenylyl cyclase, thereby altering the intracellular concentration of cyclic AMP. The cyclic AMP activates protein kinase A, which phosphorylates certain enzymes and the enzymes in turn phosphorylate motor proteins. An inhibitor of protein kinase A, KT5720, decreases the number of the Transported particles. In a stable state the cyclic AMP level stays at a normal level. Treatment with neurotransmitters causes a change in this level, which changes the activity of protein kinase A and thus decreases or enhances the phosphorylation of motor proteins. These changes are involved in the modulation of Axoplasmic Transport.

Hideaki Hori - One of the best experts on this subject based on the ideXlab platform.

  • fatty acids as an energy source for the operation of Axoplasmic Transport
    Brain Research, 2003
    Co-Authors: Toshifumi Takenaka, Hideaki Hori, Yoko Hashimoto, Hiromi Hiruma, Takafumi Ichikawa, Tadashi Kawakami
    Abstract:

    Fatty acids are utilized as a cellular energy source. In the present study, we investigated whether fatty acids could affect Axoplasmic Transport. Cultured mouse superior cervical ganglion neurons were placed in the glucose-containing medium (145 mM NaCl, 5 mM KCl, 1 mM CaCl(2), 1 mM MgCl(2), 5 mM D-glucose, 10 mM Hepes, pH 7.3, 37 degrees C), and Axoplasmic Transport of particles in neurites was observed under video-enhanced contrast microscopy. A variety of fatty acids (acetate (C2), caproate (C6), caprylate (C8), caprate (C10), 2-decenoate (C10:1), arachidonate (C20:4); 0.1-1 mM) caused a transient increase in the amount of particles Transported in both anterograde and retrograde directions. The increasing effects of fatty acids were dose-dependent. A half-maximum effective dose (ED(50)) for acetate was 0.8 mM, which is similar to the reported K(m) value of acetyl-CoA synthetase for acetate. The ED(50) for caprylate was 28 microM, which is near the K(m) value of acyl-CoA synthetase for medium- and long-chain fatty acids. Application of 5 mM malonate, an inhibitor of the citrate cycle, induced a steady-state decrease in Axoplasmic Transport, indicating that energy derived from the citrate cycle is required for the maintenance of Axoplasmic Transport. The increasing effect of acetate (1 mM) on Axoplasmic Transport was completely abolished by pretreatment with malonate (5 mM), suggesting that acetate produces ATP for Axoplasmic Transport via the citrate cycle. Alternatively, the effect of caprate (1 mM) was retained after treatment with malonate. Thus, fatty acids except acetate produce ATP probably through both the beta-oxidation pathway and the citrate cycle, increasing Axoplasmic Transport. Since the effect of fatty acids was transient, certain negative feedback mechanisms might be involved. The removal of glucose from the medium resulted in a low steady-state level of Axoplasmic Transport. Under such condition, the acetate (1 mM)-induced transient increase in Axoplasmic Transport remained. Since intracellular ATP must be low under glucose-free condition, intracellular ATP concentrations are unlikely to be involved in the feedback system. Instead, acetyl-CoA or its downstream products in the citrate cycle might lead to feedback inhibition. Application of citrate (5 mM) caused a strong decrease following a transient increase in Axoplasmic Transport, whereas no other acetyl-CoA product decreased Axoplasmic Transport. Thus, excessive citrate may be one of factors leading to feedback inhibition of metabolic pathways to arrest and reverse the increase in Axoplasmic Transport induced by fatty acids.

  • growth cone neuropilin 1 mediates collapsin 1 sema iii facilitation of antero and retrograde Axoplasmic Transport
    Journal of Neurobiology, 1999
    Co-Authors: Yoshio Goshima, Toshifumi Takenaka, Hideaki Hori, Yukio Sasaki, Tao Yang, Masako Kagoshimamaezono, Fumio Nakamura, Takuya Takahashi, Stephen M Strittmatter, Yoshimi Misu
    Abstract:

    Collapsin-1/Sema III, a member of the semaphorin family, has been implicated in axonal pathfinding as a repulsive guidance cue. Cellular and molecular mechanisms by which collapsin-1 exerts its action are not fully understood. Collapsin-1 induces growth cone collapse via a pathway which may include neuropilin-1, a cellsurface collapsin-1 binding protein, as well as intracellular CRMP-62 and heterotrimeric G proteins. We previously identified a second action of collapsin-1, the facilitation of antero- and retrograde Axoplasmic Transport. This response occurs via a mechanism distinct from that causing growth cone collapse. To investigate the possible involvement of neuropilin-1 in the action of collapsin-1 on Axoplasmic Transport, we produced a soluble neuropilin-1 (sNP-1) lacking the transmembrane and intracellular region. sNP-1 progressively displaced the dose-response curve for collapsin-1 to induce growth cone collapse to higher concentrations. sNP-1 also inhibited collapsin-1-induced augmentation of both antero- and retrograde Axoplasmic Transport. Furthermore, an anti-neuropilin-1 antibody blocked the collapsin-induced Axoplasmic Transport. These results together indicate that neuropilin-1 mediates collapsin-1 action on Axoplasmic Transport. To visualize collapsin-1 binding to endogenous neuropilin-1, we used a truncated collapsin-1-alkaline phosphatase fusion protein (CAP-4). CAP-4 stains the growth cone, neurite, and cell body. However, local application of collapsin-1 to growth cone but to neither neurite nor cell body promotes Axoplasmic Transport. Thus, growth cone NP-1 mediates the facilitatory action of collapsin-1 on antero- and retrograde Axoplasmic Transport.

  • effects of alcar on the fast Axoplasmic Transport in cultured sensory neurons of streptozotocin induced diabetic rats
    Neuroscience Research, 1999
    Co-Authors: Masato Kano, Tadashi Kawakami, Hideaki Hori, Yoko Hashimoto, Yang Tao, Yoshihiro Ishikawa, Toshifumi Takenaka
    Abstract:

    The effects of acetyl-L-carnitine (ALCAR) on fast Axoplasmic Transport were studied in cultured dorsal root ganglion (DRG) neurons of diabetic rats. Three-month-old male rats were used 7 days after streptozotocin injection. Neurons obtained from ganglia were cultured with a high concentration of glucose. The amount and the mean velocity of retrogradely Transported particles, reduced in the diabetic animal, were transiently recovered by 1 mM ALCAR. The number of particles moving at 0.8-1.2 microm/s, considered to be lysosomes, increased in the velocity distribution. ALCAR did not modify the amount and mean velocity of anterograde particles which were unaffected by diabetes, or of bidirectional particles in neurons of control rats. This study suggests that diabetic neuropathy may be relieved by ALCAR via recovering retrograde Axoplasmic Transport.

  • Axoplasmic Transport and its signal transduction mechanism
    Journal of Physiological Sciences, 1998
    Co-Authors: Toshifumi Takenaka, Tadashi Kawakami, Hideaki Hori, Yoko Hashimoto, Hiromi Hiruma, Tatsumi Kusakabe
    Abstract:

    Neuron requires a continual supply of materials synthesized in the cell body, for example a wide range of soluble proteins, membranous components, and various organelles. The Transported materials are needed to replace constituents that turn over in the membrane and organelles of the fiber and also are needed to bring substances participating in energy metabolism. Other Transported components are neurotransmitters or transmitter-related components supplied to the nerve terminals for the release and subsequent excitation of postsynaptic cells. Moreover, neurotropic substances and modulators are released from the nerve terminals to affect the functional state of the neuron. Conversely, some materials are conveyed back to the cell body. These include organelles, lysosomes, nerve growth factor, and selected small molecules such as adenosine, Ca2+, and some neurotransmitters. Axoplasmic Transport is thought to be fundamental for a variety of neuronal cell functions. Thus it may be considered that Axoplasmic Transport relates to the dynamic physiological activity of neurons; in other words, Axoplasmic Transport is supposed to express the physiological activity of neurons. In turn, as in the case for many other physiological functions, Axoplasmic Transport is possibly controlled by neuronal, hormonal, and immunological systems. Since Axoplasmic Transport supplies neuron materials toward the synapses and back to the cell body, a feedback system of regulatory mechanisms of a variety of neuronal functions might be operated through Axoplasmic Transport pathways. Although Axoplasmic Transport is the important neuronal function, its regulation is poorly understood. In this review, we focus on the dynamics of organelle Transport and its regulatory mechanisms mediated by neurotransmitters.

  • a novel action of collapsin collapsin 1 increases antero and retrograde Axoplasmic Transport independently of growth cone collapse
    Journal of Neurobiology, 1997
    Co-Authors: Yoshio Goshima, Toshifumi Takenaka, Tadashi Kawakami, Hideaki Hori, Yoko Hashimoto, Masako Kagoshimamaezono, Yoshimi Misu, Yoshinobu Sugiyama, Shuichi Takasawa, Stephen M Strittmatter
    Abstract:

    Chick collapsin-1, a member of the by a mechanism distinct from that causing growth semaphorin family, has been implicated in axonal cone collapse. Pertussis toxin (PTX) but not its B pathfinding as a repulsive guidance cue. Collapsin-1 induces growth cone collapse via a pathway which oligomer blocks collapsin-induced growth cone col- may include CRMP-62 and heterotrimeric G proteins. lapse. The holotoxin does not affect collapsin-stimu- CRMP-62 protein is related to UNC-33, a nematode lated Axoplasmic Transport. Mastoparan and a myelin neuronal protein required for appropriately directed protein NI-35 induce PTX-sensitive growth cone col- axonal extension. Mutations in unc-33 affect neural lapse but do not stimulate Axoplasmic Transport. microtubules, the basic cytoskeletal elements for axo- These results provide evidence that collapsin has a plasmic Transport. Using computer-assisted video-en- unique property to activate axonal vesicular Transport hanced differential interference contrast microscopy, systems. There are at least two distinct pathways we now demonstrate that collapsin-1 potently pro- through which collapsin exerts its actions in motes Axoplasmic Transport. Collapsin-1 doubles the developing neurons. q 1997 John Wiley & Sons, Inc. J number of antero- and retrograde-Transported organ- Neurobiol 33: 316-328, 1997 elles but not their velocity. Collapsin-1 decreases the Keywords: collapsin; Axoplasmic Transport; nerve number of stationary organelles, suggesting that the growth cone; pertussis toxin; G proteins fraction of time during which a particle is moving is

Yoko Hashimoto - One of the best experts on this subject based on the ideXlab platform.

  • fatty acids as an energy source for the operation of Axoplasmic Transport
    Brain Research, 2003
    Co-Authors: Toshifumi Takenaka, Hideaki Hori, Yoko Hashimoto, Hiromi Hiruma, Takafumi Ichikawa, Tadashi Kawakami
    Abstract:

    Fatty acids are utilized as a cellular energy source. In the present study, we investigated whether fatty acids could affect Axoplasmic Transport. Cultured mouse superior cervical ganglion neurons were placed in the glucose-containing medium (145 mM NaCl, 5 mM KCl, 1 mM CaCl(2), 1 mM MgCl(2), 5 mM D-glucose, 10 mM Hepes, pH 7.3, 37 degrees C), and Axoplasmic Transport of particles in neurites was observed under video-enhanced contrast microscopy. A variety of fatty acids (acetate (C2), caproate (C6), caprylate (C8), caprate (C10), 2-decenoate (C10:1), arachidonate (C20:4); 0.1-1 mM) caused a transient increase in the amount of particles Transported in both anterograde and retrograde directions. The increasing effects of fatty acids were dose-dependent. A half-maximum effective dose (ED(50)) for acetate was 0.8 mM, which is similar to the reported K(m) value of acetyl-CoA synthetase for acetate. The ED(50) for caprylate was 28 microM, which is near the K(m) value of acyl-CoA synthetase for medium- and long-chain fatty acids. Application of 5 mM malonate, an inhibitor of the citrate cycle, induced a steady-state decrease in Axoplasmic Transport, indicating that energy derived from the citrate cycle is required for the maintenance of Axoplasmic Transport. The increasing effect of acetate (1 mM) on Axoplasmic Transport was completely abolished by pretreatment with malonate (5 mM), suggesting that acetate produces ATP for Axoplasmic Transport via the citrate cycle. Alternatively, the effect of caprate (1 mM) was retained after treatment with malonate. Thus, fatty acids except acetate produce ATP probably through both the beta-oxidation pathway and the citrate cycle, increasing Axoplasmic Transport. Since the effect of fatty acids was transient, certain negative feedback mechanisms might be involved. The removal of glucose from the medium resulted in a low steady-state level of Axoplasmic Transport. Under such condition, the acetate (1 mM)-induced transient increase in Axoplasmic Transport remained. Since intracellular ATP must be low under glucose-free condition, intracellular ATP concentrations are unlikely to be involved in the feedback system. Instead, acetyl-CoA or its downstream products in the citrate cycle might lead to feedback inhibition. Application of citrate (5 mM) caused a strong decrease following a transient increase in Axoplasmic Transport, whereas no other acetyl-CoA product decreased Axoplasmic Transport. Thus, excessive citrate may be one of factors leading to feedback inhibition of metabolic pathways to arrest and reverse the increase in Axoplasmic Transport induced by fatty acids.

  • effects of alcar on the fast Axoplasmic Transport in cultured sensory neurons of streptozotocin induced diabetic rats
    Neuroscience Research, 1999
    Co-Authors: Masato Kano, Tadashi Kawakami, Hideaki Hori, Yoko Hashimoto, Yang Tao, Yoshihiro Ishikawa, Toshifumi Takenaka
    Abstract:

    The effects of acetyl-L-carnitine (ALCAR) on fast Axoplasmic Transport were studied in cultured dorsal root ganglion (DRG) neurons of diabetic rats. Three-month-old male rats were used 7 days after streptozotocin injection. Neurons obtained from ganglia were cultured with a high concentration of glucose. The amount and the mean velocity of retrogradely Transported particles, reduced in the diabetic animal, were transiently recovered by 1 mM ALCAR. The number of particles moving at 0.8-1.2 microm/s, considered to be lysosomes, increased in the velocity distribution. ALCAR did not modify the amount and mean velocity of anterograde particles which were unaffected by diabetes, or of bidirectional particles in neurons of control rats. This study suggests that diabetic neuropathy may be relieved by ALCAR via recovering retrograde Axoplasmic Transport.

  • Axoplasmic Transport and its signal transduction mechanism
    Journal of Physiological Sciences, 1998
    Co-Authors: Toshifumi Takenaka, Tadashi Kawakami, Hideaki Hori, Yoko Hashimoto, Hiromi Hiruma, Tatsumi Kusakabe
    Abstract:

    Neuron requires a continual supply of materials synthesized in the cell body, for example a wide range of soluble proteins, membranous components, and various organelles. The Transported materials are needed to replace constituents that turn over in the membrane and organelles of the fiber and also are needed to bring substances participating in energy metabolism. Other Transported components are neurotransmitters or transmitter-related components supplied to the nerve terminals for the release and subsequent excitation of postsynaptic cells. Moreover, neurotropic substances and modulators are released from the nerve terminals to affect the functional state of the neuron. Conversely, some materials are conveyed back to the cell body. These include organelles, lysosomes, nerve growth factor, and selected small molecules such as adenosine, Ca2+, and some neurotransmitters. Axoplasmic Transport is thought to be fundamental for a variety of neuronal cell functions. Thus it may be considered that Axoplasmic Transport relates to the dynamic physiological activity of neurons; in other words, Axoplasmic Transport is supposed to express the physiological activity of neurons. In turn, as in the case for many other physiological functions, Axoplasmic Transport is possibly controlled by neuronal, hormonal, and immunological systems. Since Axoplasmic Transport supplies neuron materials toward the synapses and back to the cell body, a feedback system of regulatory mechanisms of a variety of neuronal functions might be operated through Axoplasmic Transport pathways. Although Axoplasmic Transport is the important neuronal function, its regulation is poorly understood. In this review, we focus on the dynamics of organelle Transport and its regulatory mechanisms mediated by neurotransmitters.

  • a novel action of collapsin collapsin 1 increases antero and retrograde Axoplasmic Transport independently of growth cone collapse
    Journal of Neurobiology, 1997
    Co-Authors: Yoshio Goshima, Toshifumi Takenaka, Tadashi Kawakami, Hideaki Hori, Yoko Hashimoto, Masako Kagoshimamaezono, Yoshimi Misu, Yoshinobu Sugiyama, Shuichi Takasawa, Stephen M Strittmatter
    Abstract:

    Chick collapsin-1, a member of the by a mechanism distinct from that causing growth semaphorin family, has been implicated in axonal cone collapse. Pertussis toxin (PTX) but not its B pathfinding as a repulsive guidance cue. Collapsin-1 induces growth cone collapse via a pathway which oligomer blocks collapsin-induced growth cone col- may include CRMP-62 and heterotrimeric G proteins. lapse. The holotoxin does not affect collapsin-stimu- CRMP-62 protein is related to UNC-33, a nematode lated Axoplasmic Transport. Mastoparan and a myelin neuronal protein required for appropriately directed protein NI-35 induce PTX-sensitive growth cone col- axonal extension. Mutations in unc-33 affect neural lapse but do not stimulate Axoplasmic Transport. microtubules, the basic cytoskeletal elements for axo- These results provide evidence that collapsin has a plasmic Transport. Using computer-assisted video-en- unique property to activate axonal vesicular Transport hanced differential interference contrast microscopy, systems. There are at least two distinct pathways we now demonstrate that collapsin-1 potently pro- through which collapsin exerts its actions in motes Axoplasmic Transport. Collapsin-1 doubles the developing neurons. q 1997 John Wiley & Sons, Inc. J number of antero- and retrograde-Transported organ- Neurobiol 33: 316-328, 1997 elles but not their velocity. Collapsin-1 decreases the Keywords: collapsin; Axoplasmic Transport; nerve number of stationary organelles, suggesting that the growth cone; pertussis toxin; G proteins fraction of time during which a particle is moving is

  • effects of acetylcholine and adrenaline on Axoplasmic Transport at different regions of mouse superior cervical ganglion cells in culture
    Brain Research, 1995
    Co-Authors: Tadashi Kawakami, Toshifumi Takenaka, Hideaki Hori, Yoko Hashimoto, Tatsumi Kusakabe
    Abstract:

    Adrenaline and acetylcholine (ACh) were applied locally at three different positions in cultured superior cervical ganglion cells, i.e., cell body, neurite, and growth cone and the effects on the Axoplasmic Transport were measured with a video-enhanced microscope. Local ACh application to the cell body, neurite, and growth cone caused the same decreasing effect, but the effects of local adrenaline application were different from each other. Local adrenaline application to the cell body and growth cone caused an increase of Axoplasmic Transport, but local application at the neurite caused no effect. These data may indicate that there was a lack ofβ2 adrenergic receptors in the neurite. Desensitization of Axoplasmic Transport was also examined in the SCG neurons. Repetitive adrenaline application to the cell body caused desensitization to the stimulus of adrenaline application.

Tatsumi Kusakabe - One of the best experts on this subject based on the ideXlab platform.

  • Axoplasmic Transport and its signal transduction mechanism
    Journal of Physiological Sciences, 1998
    Co-Authors: Toshifumi Takenaka, Tadashi Kawakami, Hideaki Hori, Yoko Hashimoto, Hiromi Hiruma, Tatsumi Kusakabe
    Abstract:

    Neuron requires a continual supply of materials synthesized in the cell body, for example a wide range of soluble proteins, membranous components, and various organelles. The Transported materials are needed to replace constituents that turn over in the membrane and organelles of the fiber and also are needed to bring substances participating in energy metabolism. Other Transported components are neurotransmitters or transmitter-related components supplied to the nerve terminals for the release and subsequent excitation of postsynaptic cells. Moreover, neurotropic substances and modulators are released from the nerve terminals to affect the functional state of the neuron. Conversely, some materials are conveyed back to the cell body. These include organelles, lysosomes, nerve growth factor, and selected small molecules such as adenosine, Ca2+, and some neurotransmitters. Axoplasmic Transport is thought to be fundamental for a variety of neuronal cell functions. Thus it may be considered that Axoplasmic Transport relates to the dynamic physiological activity of neurons; in other words, Axoplasmic Transport is supposed to express the physiological activity of neurons. In turn, as in the case for many other physiological functions, Axoplasmic Transport is possibly controlled by neuronal, hormonal, and immunological systems. Since Axoplasmic Transport supplies neuron materials toward the synapses and back to the cell body, a feedback system of regulatory mechanisms of a variety of neuronal functions might be operated through Axoplasmic Transport pathways. Although Axoplasmic Transport is the important neuronal function, its regulation is poorly understood. In this review, we focus on the dynamics of organelle Transport and its regulatory mechanisms mediated by neurotransmitters.

  • effects of acetylcholine and adrenaline on Axoplasmic Transport at different regions of mouse superior cervical ganglion cells in culture
    Brain Research, 1995
    Co-Authors: Tadashi Kawakami, Toshifumi Takenaka, Hideaki Hori, Yoko Hashimoto, Tatsumi Kusakabe
    Abstract:

    Adrenaline and acetylcholine (ACh) were applied locally at three different positions in cultured superior cervical ganglion cells, i.e., cell body, neurite, and growth cone and the effects on the Axoplasmic Transport were measured with a video-enhanced microscope. Local ACh application to the cell body, neurite, and growth cone caused the same decreasing effect, but the effects of local adrenaline application were different from each other. Local adrenaline application to the cell body and growth cone caused an increase of Axoplasmic Transport, but local application at the neurite caused no effect. These data may indicate that there was a lack ofβ2 adrenergic receptors in the neurite. Desensitization of Axoplasmic Transport was also examined in the SCG neurons. Repetitive adrenaline application to the cell body caused desensitization to the stimulus of adrenaline application.

  • mechanism of inhibitory action of capsaicin on particulate Axoplasmic Transport in sensory neurons in culture
    Journal of Neurobiology, 1993
    Co-Authors: Tadashi Kawakami, Tatsumi Kusakabe, Yoko Bandou, Naoshi Hikawa, Hideki Gotoh, Masato Kano, Toshifumi Takenaka
    Abstract:

    The inhibitory effect of capsaicin on Axoplasmic Transport in cultured dorsal root ganglion cells was analyzed by video-enhanced contrast microscopy. Capsaicin inhibited particle Transports in a dose-dependent manner, irrespective of the diameter of axons. The effect of capsaicin was reversible at low concentrations. Capsaicin affected both the anterograde and retrograde Transport. Large organelles were more sensitive to capsaicin than small ones in the retrograde Transport. An experiment using calcium-sensitive dye, Fura 2, indicated that capsaicin raised the intraneuronal free calcium concentration preceding the inhibition of the Transport. Electron microscopy revealed that microtubules and neurofilaments are disorganized and disoriented by capsaicin. We reached a conclusion that capsaicin inhibits fast Axoplasmic Transport of both anterograde and retrograde directions in all types of somatosensory neurons in culture by disorganizing intraaxonal cytoskeletal structures, through the elevated intracellular Ca2+ concentration.