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Takafumi Sakai - One of the best experts on this subject based on the ideXlab platform.

  • molecular identification of ghs r and gpr38 in sUncus murinus
    Peptides, 2012
    Co-Authors: Airi Suzuki, Sayaka Aizawa, Chihiro Tsutsui, Anupom Mondal, Koike Kanako, Ichiro Sakata, Yuko Ishida, Takafumi Sakai
    Abstract:

    Abstract We previously identified ghrelin and motilin genes in SUncus murinus (sUncus), and also revealed that motilin induces phase III-like strong contractions in the sUncus stomach in vivo, as observed in humans and dogs. Moreover, repeated migrating motor complexes were found in the gastrointestinal tract of sUncus at regular 120-min intervals. We therefore proposed sUncus as a small laboratory animal model for the study of gastrointestinal motility. In the present study, we identified growth hormone secretagogue receptor (GHS-R) and motilin receptor (GPR38) genes in the sUncus. We also examined their tissue distribution throughout the body. The amino acids of sUncus GHS-R and GPR38 showed high homology with those of other mammals and shared 42% amino acid identity. RT-PCR showed that both the receptors were expressed in the hypothalamus, medulla oblongata, pituitary gland and the nodose ganglion in the central nervous system. In addition, GHS-R mRNA expressions were detected throughout the stomach and intestine, whereas GPR38 was expressed in the gastric muscle layer, lower intestine, lungs, heart, and pituitary gland. These results suggest that ghrelin and motilin affect gut motility and energy metabolism via specific receptors expressed in the gastrointestinal tract and/or in the central nervous system of sUncus.

  • physiological characteristics of gastric contractions and circadian gastric motility in the free moving conscious house musk shrew sUncus murinus
    American Journal of Physiology-regulatory Integrative and Comparative Physiology, 2010
    Co-Authors: Satoshi Sakahara, Kanako Koike, Satoya Hoshino, Ichiro Sakata, Toku Takahashi, Takafumi Sakai
    Abstract:

    Although many studies have demonstrated the physiological action of motilin on the migrating motor complex, the precise mechanisms remain obscure. To obtain new insights into the mechanisms, we focused on the house musk shrew ( SUncus murinus , sUncus used as a laboratory name) as a small model animal for in vivo motilin study, and we studied the physiological characteristics of sUncus gastrointestinal motility. Strain gauge transducers were implanted on the serosa of the gastric body and duodenum, and we recorded gastrointestinal contractions in the free-moving conscious sUncus and also examined the effects of intravenous infusion of various agents on gastrointestinal motility. During the fasted state, the sUncus stomach and duodenum showed clear migrating phase III contractions (intervals of 80–150 min) as found in humans and dogs. Motilin (bolus injection, 100–300 ng/kg; continuous infusion, 10–100 ng·kg−1·min−1) and erythromycin (80 μg·kg−1·min−1) induced gastric phase III contractions, and motilin injection also increased the gastric motility index in a dose-dependent manner ( P < 0.05, vs. saline). Pretreatment with atropine completely abolished the motilin-induced gastric phase III contractions. On the other hand, in the free-feeding condition, the sUncus showed a relatively long fasting period in the light phase followed by spontaneous gastric phase III contractions. The results suggest that the sUncus has almost the same gastrointestinal motility and motilin response as those found in humans and dogs, and we propose the sUncus as a new small model animal for studying gastrointestinal motility and motilin in vivo.

  • identification of ghrelin in the house musk shrew sUncus murinus cdna cloning peptide purification and tissue distribution
    Peptides, 2009
    Co-Authors: Yuko Ishida, Chihiro Tsutsui, Satoshi Sakahara, Hiroyuki Kaiya, Ichiro Sakata, Takafumi Sakai
    Abstract:

    Ghrelin is the endogenous ligand for the growth hormone (GH) secretagogue receptor, and the sequence of ghrelin has been determined in many species from fish to mammals. In the present study, to reveal the production of ghrelin in the house musk shrew (SUncus murinus, order: Insectivora, sUncus is used as a laboratory name), we determined the cDNA sequence and structure of sUncus ghrelin and also demonstrated the ghrelin-producing cells in the gastrointestinal tract. Results of cDNA cloning and mass spectrometry analysis revealed that sUncus ghrelin is composed of 18 or 26 amino acid residues and that the 3rd Ser was acylated mainly by n-octanoic acid. The 10 amino acids of the N-terminal region of sUncus mature ghrelin were consistent with those of other mammals. Quantitative RT-PCR revealed that sUncus ghrelin mRNA is highly expressed in the gastric corpus and pyloric antrum, and low expression levels were found in various tissues, including the intestinal tract. Ghrelin cells were found only in the corpus and antrum by immunohistochemistry and in situ hybridization, and most of the ghrelin cells were closed-type cells with relatively rich cytoplasm and scattered in the glandular body and base of the gastric mucosa. The density of ghrelin cells in the corpus was significantly greater than that in the antrum. The results of this study together with our recent results regarding motilin production in the sUncus indicate that the sUncus will be a useful model animal for study of physiological function of the motilin/ghrelin family.

  • house musk shrew sUncus murinus order insectivora as a new model animal for motilin study
    Peptides, 2009
    Co-Authors: Chihiro Tsutsui, Kie Kajihara, Takatsugu Yanaka, Zen Itoh, Ichiro Sakata, Takafumi Sakai
    Abstract:

    Although many studies have demonstrated the action of motilin on migrating motor complex by using human subjects and relatively large animals, the precise physiological mechanisms of motilin remain obscure. One reason for the lack of progress in this research field is that large animals are generally not suitable for molecular-level study. To overcome this problem, in this study, we focused on the house musk shrew (SUncus murinus, order: Insectivora, sUncus named as laboratory strain) as a small model animal, and we present here the results of motilin gene cloning and its availability for motilin study. The motilin gene has a high homology sequence with that of other mammals, including humans. SUncus motilin is predicted to exist as a 117-residue prepropeptide that undergoes proteolytic cleavage to form a 22-amino-acid mature peptide. The results of RT-PCR showed that motilin mRNA is highly expressed in the upper small intestine, and low levels of expression were found in many tissues. Morphological analysis revealed that sUncus motilin-producing cells were present in the upper small intestinal mucosal layer but not in the myenteric plexus. Administration of sUncus motilin to prepared muscle strips of rabbit duodenum showed almost the same contractile effect as that of human motilin. Moreover, sUncus stomach preparations clearly responded to sUncus or human motilin stimulation. To our knowledge, this is the first report that physiological active motilin was determined in small laboratory animals, and the results of this study suggest that sUncus is a suitable model animal for studying the motilin-ghrelin family.

Hirotaka Sakamoto - One of the best experts on this subject based on the ideXlab platform.

  • identification of the sexually dimorphic gastrin releasing peptide system in the lumbosacral spinal cord that controls male reproductive function in the mouse and asian house musk shrew sUncus murinus
    The Journal of Comparative Neurology, 2017
    Co-Authors: Kei Tamura, Takamichi Jogahara, Yasuhisa Kobayashi, Asuka Hirooka, Keiko Takanami, Tatsuya Sakamoto, Hirotaka Sakamoto
    Abstract:

    Several regions of the brain and spinal cord control male reproductive function. We previously demonstrated that the gastrin-releasing peptide (GRP) system, located in the lumbosacral spinal cord of rats, controls spinal centers to promote penile reflexes during male copulatory behavior. However, little information exists on the male-specific spinal GRP system in animals other than rats. The objective of this study was to examine the functional generality of the spinal GRP system in mammals using the Asian house musk shrew (SUncus murinus; sUncus named as the laboratory strain), a specialized placental mammal model. Mice are also used for a representative model of small laboratory animals. We first isolated complementary DNA encoding GRP in sUncus. Phylogenetic analysis revealed that sUncus preproGRP was clustered to an independent branch. Reverse transcription-PCR showed that GRP and its receptor mRNAs were both expressed in the lumbar spinal cord of sUncus and mice. Immunohistochemistry for GRP demonstrated that the sexually dimorphic GRP system and male-specific expression/distribution patterns of GRP in the lumbosacral spinal cord in sUncus are similar to those of mice. In sUncus, we further found that most GRP-expressing neurons in males also express androgen receptors, suggesting that this male-dominant system in sUncus is also androgen-dependent. Taken together, these results indicate that the sexually dimorphic spinal GRP system exists not only in mice but also in sUncus, suggesting that this system is a conserved property in mammals. This article is protected by copyright. All rights reserved.

Kei Tamura - One of the best experts on this subject based on the ideXlab platform.

  • identification of the sexually dimorphic gastrin releasing peptide system in the lumbosacral spinal cord that controls male reproductive function in the mouse and asian house musk shrew sUncus murinus
    The Journal of Comparative Neurology, 2017
    Co-Authors: Kei Tamura, Takamichi Jogahara, Yasuhisa Kobayashi, Asuka Hirooka, Keiko Takanami, Tatsuya Sakamoto, Hirotaka Sakamoto
    Abstract:

    Several regions of the brain and spinal cord control male reproductive function. We previously demonstrated that the gastrin-releasing peptide (GRP) system, located in the lumbosacral spinal cord of rats, controls spinal centers to promote penile reflexes during male copulatory behavior. However, little information exists on the male-specific spinal GRP system in animals other than rats. The objective of this study was to examine the functional generality of the spinal GRP system in mammals using the Asian house musk shrew (SUncus murinus; sUncus named as the laboratory strain), a specialized placental mammal model. Mice are also used for a representative model of small laboratory animals. We first isolated complementary DNA encoding GRP in sUncus. Phylogenetic analysis revealed that sUncus preproGRP was clustered to an independent branch. Reverse transcription-PCR showed that GRP and its receptor mRNAs were both expressed in the lumbar spinal cord of sUncus and mice. Immunohistochemistry for GRP demonstrated that the sexually dimorphic GRP system and male-specific expression/distribution patterns of GRP in the lumbosacral spinal cord in sUncus are similar to those of mice. In sUncus, we further found that most GRP-expressing neurons in males also express androgen receptors, suggesting that this male-dominant system in sUncus is also androgen-dependent. Taken together, these results indicate that the sexually dimorphic spinal GRP system exists not only in mice but also in sUncus, suggesting that this system is a conserved property in mammals. This article is protected by copyright. All rights reserved.

Ichiro Sakata - One of the best experts on this subject based on the ideXlab platform.

  • molecular identification of ghs r and gpr38 in sUncus murinus
    Peptides, 2012
    Co-Authors: Airi Suzuki, Sayaka Aizawa, Chihiro Tsutsui, Anupom Mondal, Koike Kanako, Ichiro Sakata, Yuko Ishida, Takafumi Sakai
    Abstract:

    Abstract We previously identified ghrelin and motilin genes in SUncus murinus (sUncus), and also revealed that motilin induces phase III-like strong contractions in the sUncus stomach in vivo, as observed in humans and dogs. Moreover, repeated migrating motor complexes were found in the gastrointestinal tract of sUncus at regular 120-min intervals. We therefore proposed sUncus as a small laboratory animal model for the study of gastrointestinal motility. In the present study, we identified growth hormone secretagogue receptor (GHS-R) and motilin receptor (GPR38) genes in the sUncus. We also examined their tissue distribution throughout the body. The amino acids of sUncus GHS-R and GPR38 showed high homology with those of other mammals and shared 42% amino acid identity. RT-PCR showed that both the receptors were expressed in the hypothalamus, medulla oblongata, pituitary gland and the nodose ganglion in the central nervous system. In addition, GHS-R mRNA expressions were detected throughout the stomach and intestine, whereas GPR38 was expressed in the gastric muscle layer, lower intestine, lungs, heart, and pituitary gland. These results suggest that ghrelin and motilin affect gut motility and energy metabolism via specific receptors expressed in the gastrointestinal tract and/or in the central nervous system of sUncus.

  • physiological characteristics of gastric contractions and circadian gastric motility in the free moving conscious house musk shrew sUncus murinus
    American Journal of Physiology-regulatory Integrative and Comparative Physiology, 2010
    Co-Authors: Satoshi Sakahara, Kanako Koike, Satoya Hoshino, Ichiro Sakata, Toku Takahashi, Takafumi Sakai
    Abstract:

    Although many studies have demonstrated the physiological action of motilin on the migrating motor complex, the precise mechanisms remain obscure. To obtain new insights into the mechanisms, we focused on the house musk shrew ( SUncus murinus , sUncus used as a laboratory name) as a small model animal for in vivo motilin study, and we studied the physiological characteristics of sUncus gastrointestinal motility. Strain gauge transducers were implanted on the serosa of the gastric body and duodenum, and we recorded gastrointestinal contractions in the free-moving conscious sUncus and also examined the effects of intravenous infusion of various agents on gastrointestinal motility. During the fasted state, the sUncus stomach and duodenum showed clear migrating phase III contractions (intervals of 80–150 min) as found in humans and dogs. Motilin (bolus injection, 100–300 ng/kg; continuous infusion, 10–100 ng·kg−1·min−1) and erythromycin (80 μg·kg−1·min−1) induced gastric phase III contractions, and motilin injection also increased the gastric motility index in a dose-dependent manner ( P < 0.05, vs. saline). Pretreatment with atropine completely abolished the motilin-induced gastric phase III contractions. On the other hand, in the free-feeding condition, the sUncus showed a relatively long fasting period in the light phase followed by spontaneous gastric phase III contractions. The results suggest that the sUncus has almost the same gastrointestinal motility and motilin response as those found in humans and dogs, and we propose the sUncus as a new small model animal for studying gastrointestinal motility and motilin in vivo.

  • identification of ghrelin in the house musk shrew sUncus murinus cdna cloning peptide purification and tissue distribution
    Peptides, 2009
    Co-Authors: Yuko Ishida, Chihiro Tsutsui, Satoshi Sakahara, Hiroyuki Kaiya, Ichiro Sakata, Takafumi Sakai
    Abstract:

    Ghrelin is the endogenous ligand for the growth hormone (GH) secretagogue receptor, and the sequence of ghrelin has been determined in many species from fish to mammals. In the present study, to reveal the production of ghrelin in the house musk shrew (SUncus murinus, order: Insectivora, sUncus is used as a laboratory name), we determined the cDNA sequence and structure of sUncus ghrelin and also demonstrated the ghrelin-producing cells in the gastrointestinal tract. Results of cDNA cloning and mass spectrometry analysis revealed that sUncus ghrelin is composed of 18 or 26 amino acid residues and that the 3rd Ser was acylated mainly by n-octanoic acid. The 10 amino acids of the N-terminal region of sUncus mature ghrelin were consistent with those of other mammals. Quantitative RT-PCR revealed that sUncus ghrelin mRNA is highly expressed in the gastric corpus and pyloric antrum, and low expression levels were found in various tissues, including the intestinal tract. Ghrelin cells were found only in the corpus and antrum by immunohistochemistry and in situ hybridization, and most of the ghrelin cells were closed-type cells with relatively rich cytoplasm and scattered in the glandular body and base of the gastric mucosa. The density of ghrelin cells in the corpus was significantly greater than that in the antrum. The results of this study together with our recent results regarding motilin production in the sUncus indicate that the sUncus will be a useful model animal for study of physiological function of the motilin/ghrelin family.

  • house musk shrew sUncus murinus order insectivora as a new model animal for motilin study
    Peptides, 2009
    Co-Authors: Chihiro Tsutsui, Kie Kajihara, Takatsugu Yanaka, Zen Itoh, Ichiro Sakata, Takafumi Sakai
    Abstract:

    Although many studies have demonstrated the action of motilin on migrating motor complex by using human subjects and relatively large animals, the precise physiological mechanisms of motilin remain obscure. One reason for the lack of progress in this research field is that large animals are generally not suitable for molecular-level study. To overcome this problem, in this study, we focused on the house musk shrew (SUncus murinus, order: Insectivora, sUncus named as laboratory strain) as a small model animal, and we present here the results of motilin gene cloning and its availability for motilin study. The motilin gene has a high homology sequence with that of other mammals, including humans. SUncus motilin is predicted to exist as a 117-residue prepropeptide that undergoes proteolytic cleavage to form a 22-amino-acid mature peptide. The results of RT-PCR showed that motilin mRNA is highly expressed in the upper small intestine, and low levels of expression were found in many tissues. Morphological analysis revealed that sUncus motilin-producing cells were present in the upper small intestinal mucosal layer but not in the myenteric plexus. Administration of sUncus motilin to prepared muscle strips of rabbit duodenum showed almost the same contractile effect as that of human motilin. Moreover, sUncus stomach preparations clearly responded to sUncus or human motilin stimulation. To our knowledge, this is the first report that physiological active motilin was determined in small laboratory animals, and the results of this study suggest that sUncus is a suitable model animal for studying the motilin-ghrelin family.

Roggero Angela - One of the best experts on this subject based on the ideXlab platform.

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