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H. Elliott Albers - One of the best experts on this subject based on the ideXlab platform.

  • Injection of oxytocin into the medial Preoptic-Anterior Hypothalamus increases ultrasound production by female hamsters.
    Peptides, 1998
    Co-Authors: Owen R. Floody, Timothy T. Cooper, H. Elliott Albers
    Abstract:

    Recent studies of hamsters have documented the facilitation of lordosis and other sociosexual responses by injections of oxytocin (OXT) into the medial Preoptic area-Anterior Hypothalamus (MPOA-AH). These data suggest the regulation of social interaction and bonds by OXT. In turn, this suggests that OXT could act in the MPOA-AH to control other behaviors involved in the initiation or maintenance of social contact, including the ultrasonic vocalizations that female hamsters use to alert and attract potential mates. To test this possibility, we compared the ultrasound rates of 11 naturally estrous hamsters before and after injections of OXT (200 ng/200 nl of saline) or saline (200 nl) into the MPOA-AH. The data revealed a clear facilitation of ultrasound rate 30 min after OXT treatment. This result suggests the modulation of ultrasound rate by endogenous OXT acting within the MPOA-AH. It extends the range of social behaviors sensitive to control by OXT and supports the possibility that OXT acts within the MPOA-AH to facilitate a variety of behaviors involved in the establishment or maintenance of the social interactions required for successful reproduction. At the same time, these data extend earlier observations linking ultrasound production to the MPOA-AH, and begin to describe the peptidergic mechanisms controlling this form of reproductive behavior.

  • OVARIAN HORMONES ALTER THE BEHAVIORAL RESPONSE OF THE MEDIAL Preoptic Anterior Hypothalamus TO ARGININE-VASOPRESSIN
    Peptides, 1996
    Co-Authors: H. Elliott Albers, Mary Karom, D. Carol Whitman
    Abstract:

    Abstract In Syrian hamsters ( Mesocricetus autatus ) arginine-vasopressin (AVP) within the medial Preoptic-Anterior Hypothalamus (MPOA-AH) plays a critical role in the control of a hormone-dependent behavior called flank marking. The present study investigated whether ovarian hormones influence flank marking by altering the response of the MPOA-AH to AVP. The amount of flank marking stimulated by microinjection of AVP (9 μ M in 200 nl saline) into the MPOA-AH varied significantly over the 4 days of the estrous cycle with the lowest levels of flank marking observed on estrus. A second experiment demonstrated that administration of progesterone significantly reduced AVP-stimulated flank marking in estradiol-treated ovariectomized hamsters. These data support the hypothesis that the changing levels of estradiol and progesterone during the estrous cycle influence flank marking by altering the sensitivity or response of the MPOA-AH to AVP.

  • Arginine-vasopressin immunoreactivity is not altered by photoperiod or gonadal hormones in the Syrian hamster (Mesocricetus auratus).
    Brain Research, 1991
    Co-Authors: H. Elliott Albers, Ceylon M. Rowland, Craig F. Ferris
    Abstract:

    The present study examined whether gonadal hormones or photoperiodic control influence arginine-vasopressin (AVP) immunoreactivity in the Syrian hamster (Mesocricetus auratus) as has been reported in several other rodent species. Male hamsters were castrated or sham-castrated and exposed to LD 14/10 or LD 6/18 for 13 weeks. Photoperiod and castration significantly altered body weight and the levels of circulating testosterone. In sham-castrates, testis width was significantly reduced in hamsters housed in LD 6/18. In contrast, photoperiod and castration produced no detectable alterations in AVP immunoreactivity in various CNS sites including the bed nucleus of the stria terminales, the lateral septum and medial Preoptic-Anterior Hypothalamus when measured by immunocytochemistry and radioimmunoassay of tissue punches. These data provide no evidence that AVP is regulated by either gonadal hormones or photoperiodic mechanisms in the Syrian hamster.

Khalid Benamar - One of the best experts on this subject based on the ideXlab platform.

  • Functional interaction between HIV-gp120 and opioid system in the Preoptic Anterior Hypothalamus.
    Drug and alcohol dependence, 2013
    Co-Authors: Jonathan Palma, Mary E. Abood, Mary F. Barbe, Khalid Benamar
    Abstract:

    Background Recently we found that fever (part of HIV-related wasting) is induced by the action of the human immunodeficiency virus-1 (HIV-1) envelope glycoprotein (gp120) in the Preoptic Anterior Hypothalamus (POAH). As the opioid system plays a role in the pathogenesis of HIV-1, in the present study we sought to examine the capacity of the opioid system to regulate the febrile response induced by gp120.

  • A new brain area affected by 3,4-methylenedioxymethamphetamine: A microdialysis-biotelemetry study.
    European journal of pharmacology, 2008
    Co-Authors: Khalid Benamar, Ellen B Geller, Martin W Adler
    Abstract:

    The widespread abuse of 3,4-methylenedioxymethamphetamine (MDMA) has intensified the need to learn more about this drug (e.g. its effects, its mechanism of action, brain areas affected). MDMA-induced hyperthermia is a severe physiological event not only because it can produce severe adverse consequences in human as well as experimental animals, but also because it plays a major role in determining the severity of the long-term MDMA-induced neurotoxicity that occurs. However, the effects of MDMA on the Preoptic Anterior Hypothalamus, the main brain area responsible for control of body temperature, are still unknown. In vivo microdialysis-biotelemetry and pharmacological testing were used to determine whether the Preoptic Anterior Hypothalamus is among the brain areas affected by MDMA by investigating the role of the dopamine neurotransmitter system. We examined the effect of a hyperthermic dose of MDMA on the extracellular level of dopamine in the Preoptic Anterior Hypothalamus, and whether this effect is related to the acute hyperthermic response. The administration of a hyperthermic dose of MDMA (20 mg/kg) is accompanied by an increase in the extracellular level of dopamine in the Preoptic Anterior Hypothalamus. Both the hyperthermia and augmented level of dopamine in the Preoptic Anterior Hypothalamus after intraperitoneal injection of MDMA were significantly reduced by the pretreatment with D(1)-selective dopamine receptor antagonist, R-(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzapine (SCH 23390). These data provide the first in vivo evidence that the effects of MDMA extend to Preoptic Anterior Hypothalamus.

  • A new brain area affected by 3,4-methylenedioxymethamphetamine: A microdialysis–biotelemetry study
    European Journal of Pharmacology, 2008
    Co-Authors: Khalid Benamar, Ellen B Geller, Martin W Adler
    Abstract:

    Abstract The widespread abuse of 3,4-methylenedioxymethamphetamine (MDMA) has intensified the need to learn more about this drug (e.g. its effects, its mechanism of action, brain areas affected). MDMA-induced hyperthermia is a severe physiological event not only because it can produce severe adverse consequences in human as well as experimental animals, but also because it plays a major role in determining the severity of the long-term MDMA-induced neurotoxicity that occurs. However, the effects of MDMA on the Preoptic Anterior Hypothalamus, the main brain area responsible for control of body temperature, are still unknown. In vivo microdialysis–biotelemetry and pharmacological testing were used to determine whether the Preoptic Anterior Hypothalamus is among the brain areas affected by MDMA by investigating the role of the dopamine neurotransmitter system. We examined the effect of a hyperthermic dose of MDMA on the extracellular level of dopamine in the Preoptic Anterior Hypothalamus, and whether this effect is related to the acute hyperthermic response. The administration of a hyperthermic dose of MDMA (20 mg/kg) is accompanied by an increase in the extracellular level of dopamine in the Preoptic Anterior Hypothalamus. Both the hyperthermia and augmented level of dopamine in the Preoptic Anterior Hypothalamus after intraperitoneal injection of MDMA were significantly reduced by the pretreatment with D 1 -selective dopamine receptor antagonist, R -(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1 H -3-benzapine (SCH 23390). These data provide the first in vivo evidence that the effects of MDMA extend to Preoptic Anterior Hypothalamus.

  • Intrahypothalamic injection of deltorphin-II alters body temperature in rats.
    Brain research, 2004
    Co-Authors: Khalid Benamar, Ellen B Geller, Scott M Rawls, Martin W Adler
    Abstract:

    The present study investigated the effect of H-Try-d-Ala-Phe-Glu-Val-Gly-NH2 deltorphin-II, a selective delta-2 agonist, and [d-Pen(2),d-Pen(5)]enkephalin, a selective delta-1 agonist, on body temperature in the rat. Microinjected into the Preoptic Anterior Hypothalamus (POAH), deltorphin-II (0.1-1 microg) produced an immediate dose-related hyperthermia following injection. Injection of the delta-2 antagonist naltriben into the Preoptic Anterior Hypothalamus (1 microg, 30 min prior to deltorphin-II) significantly attenuated the deltorphin-II-induced hyperthermia. Microinjection of [d-Pen(2),d-Pen(5)]enkephalin into the POAH (0.1-3 microg) did not affect Tb. The data demonstrate that delta-2 receptors are involved in the mediation of Tb effects, and deltorphin-II exerts its action directly on thermosensitive cells of the Preoptic Anterior Hypothalamus. Delta-1 opioid receptors do not appear to be involved in the control of body temperature.

  • Blockade of lipopolysaccharide-induced fever by a μ-opioid receptor-selective antagonist in rats
    European journal of pharmacology, 2000
    Co-Authors: Khalid Benamar, Ellen B Geller, Li Xin, Martin W Adler
    Abstract:

    The endogenous opioid system has been found to be involved in fever caused by pyrogens. In the present study, we have investigated the role of the mu-opioid receptor in the brain in fever induced by lipopolysaccharide. Rats were microinjected with 1 microg of the mu-opioid receptor-selective antagonist, cyclic D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH(2) (CTAP), into the Preoptic Anterior Hypothalamus. Thirty minutes later, lipopolysaccharide (50 microg/kg) was injected intraperitoneally (i.p.). CTAP reduced by 1 degrees C the fever induced by lipopolysaccharide. However, it did not affect lipopolysaccharide fever when it was given 3 h after lipopolysaccharide injection. These data indicate that mu-opioid receptors within the Preoptic Anterior Hypothalamus mediate the initiation of lipopolysaccharide fever and suggest that the opioid system is involved in the pathogenesis of fever in rats.

H. E. Albers - One of the best experts on this subject based on the ideXlab platform.

  • Glutamate and vasopressin interact to control scent marking in Syrian hamsters (Mesocricetus auratus).
    Brain research, 1996
    Co-Authors: M Bamshad, T T Cooper, M Karom, H. E. Albers
    Abstract:

    In Syrian hamsters, vasopressin (AVP) in the medial Preoptic-Anterior Hypothalamus (MPOA-AH) controls a form of scent marking called flank marking. Another neurochemical signal that may interact with AVP to control flank marking is glutamate. We tested the hypothesis that glutamate interacts with AVP in the MPOA-AH to regulate flank marking. On day 1, AVP was microinjected into the MPOA-AH. On day 2, AVP was microinjected as a cocktail combining either AP-5, a NMDA antagonist, or GAMS, a non-NMDA antagonist or propranolol, a beta norepinephrine antagonist. On day 3, AVP alone was microinjected. Hamsters engaged in high levels of marking in response to AVP alone or to a combination of AVP and propranolol. In contrast, the frequency of marking was significantly reduced in response to a combination of either AVP and AP-5 or AVP and GAMS. These data support the hypothesis that stimulation of flank marking by AVP within the MPOA-AH requires the activity of glutamate.

  • Estradiol increases the behavioral response to arginine vasopressin (AVP) in the medial Preoptic-Anterior Hypothalamus.
    Peptides, 1993
    Co-Authors: Kim L. Huhman, H. E. Albers
    Abstract:

    Abstract Flank marking, a form of hamster scent marking controlled by arginine vasopressin (AVP) in the medial Preoptic-Anterior Hypothalamus (MPOA-AH), is altered by circulating levels of gonadal hormones. We hypothesized that gonadal hormones influence flank marking either by altering the availability of AVP for release in the MPOA-AH or by altering the sensitivity or responsiveness of MPOA-AH neurons to AVP. We examined the levels of AVP immunoreactivity (AVP-IR) over the estrous cycle in the MPOA-AH and other areas. Arginine vasopressin immunoreactivity did not vary in the areas examined as a function of the stage of the estrous cycle. In Experiment 2 we measured flank marking after MPOA-AH microinjection of AVP in ovariectomized hamsters receiving estradiol or empty Silastic capsules. Hamsters implanted with estradiol capsules marked significantly more in response to AVP than did hamsters receiving no hormone replacement. These results support the hypothesis that estradiol influences flank marking by altering the sensitivity or responsiveness of the MPOA-AH or its efferents to AVP. Additionally, we observed an unexpected effect of AVP in estradiol-treated hamsters. After microinjection with 90 μ M AVP, lordosis occurred spontaneously in 60% of the hamsters even though no male was present. We suggest that female hamsters may be a useful model to further investigate the role of AVP and AVP-like peptides in female sexual behavior.

Martin W Adler - One of the best experts on this subject based on the ideXlab platform.

  • A new brain area affected by 3,4-methylenedioxymethamphetamine: A microdialysis-biotelemetry study.
    European journal of pharmacology, 2008
    Co-Authors: Khalid Benamar, Ellen B Geller, Martin W Adler
    Abstract:

    The widespread abuse of 3,4-methylenedioxymethamphetamine (MDMA) has intensified the need to learn more about this drug (e.g. its effects, its mechanism of action, brain areas affected). MDMA-induced hyperthermia is a severe physiological event not only because it can produce severe adverse consequences in human as well as experimental animals, but also because it plays a major role in determining the severity of the long-term MDMA-induced neurotoxicity that occurs. However, the effects of MDMA on the Preoptic Anterior Hypothalamus, the main brain area responsible for control of body temperature, are still unknown. In vivo microdialysis-biotelemetry and pharmacological testing were used to determine whether the Preoptic Anterior Hypothalamus is among the brain areas affected by MDMA by investigating the role of the dopamine neurotransmitter system. We examined the effect of a hyperthermic dose of MDMA on the extracellular level of dopamine in the Preoptic Anterior Hypothalamus, and whether this effect is related to the acute hyperthermic response. The administration of a hyperthermic dose of MDMA (20 mg/kg) is accompanied by an increase in the extracellular level of dopamine in the Preoptic Anterior Hypothalamus. Both the hyperthermia and augmented level of dopamine in the Preoptic Anterior Hypothalamus after intraperitoneal injection of MDMA were significantly reduced by the pretreatment with D(1)-selective dopamine receptor antagonist, R-(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzapine (SCH 23390). These data provide the first in vivo evidence that the effects of MDMA extend to Preoptic Anterior Hypothalamus.

  • A new brain area affected by 3,4-methylenedioxymethamphetamine: A microdialysis–biotelemetry study
    European Journal of Pharmacology, 2008
    Co-Authors: Khalid Benamar, Ellen B Geller, Martin W Adler
    Abstract:

    Abstract The widespread abuse of 3,4-methylenedioxymethamphetamine (MDMA) has intensified the need to learn more about this drug (e.g. its effects, its mechanism of action, brain areas affected). MDMA-induced hyperthermia is a severe physiological event not only because it can produce severe adverse consequences in human as well as experimental animals, but also because it plays a major role in determining the severity of the long-term MDMA-induced neurotoxicity that occurs. However, the effects of MDMA on the Preoptic Anterior Hypothalamus, the main brain area responsible for control of body temperature, are still unknown. In vivo microdialysis–biotelemetry and pharmacological testing were used to determine whether the Preoptic Anterior Hypothalamus is among the brain areas affected by MDMA by investigating the role of the dopamine neurotransmitter system. We examined the effect of a hyperthermic dose of MDMA on the extracellular level of dopamine in the Preoptic Anterior Hypothalamus, and whether this effect is related to the acute hyperthermic response. The administration of a hyperthermic dose of MDMA (20 mg/kg) is accompanied by an increase in the extracellular level of dopamine in the Preoptic Anterior Hypothalamus. Both the hyperthermia and augmented level of dopamine in the Preoptic Anterior Hypothalamus after intraperitoneal injection of MDMA were significantly reduced by the pretreatment with D 1 -selective dopamine receptor antagonist, R -(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1 H -3-benzapine (SCH 23390). These data provide the first in vivo evidence that the effects of MDMA extend to Preoptic Anterior Hypothalamus.

  • Intrahypothalamic injection of deltorphin-II alters body temperature in rats.
    Brain research, 2004
    Co-Authors: Khalid Benamar, Ellen B Geller, Scott M Rawls, Martin W Adler
    Abstract:

    The present study investigated the effect of H-Try-d-Ala-Phe-Glu-Val-Gly-NH2 deltorphin-II, a selective delta-2 agonist, and [d-Pen(2),d-Pen(5)]enkephalin, a selective delta-1 agonist, on body temperature in the rat. Microinjected into the Preoptic Anterior Hypothalamus (POAH), deltorphin-II (0.1-1 microg) produced an immediate dose-related hyperthermia following injection. Injection of the delta-2 antagonist naltriben into the Preoptic Anterior Hypothalamus (1 microg, 30 min prior to deltorphin-II) significantly attenuated the deltorphin-II-induced hyperthermia. Microinjection of [d-Pen(2),d-Pen(5)]enkephalin into the POAH (0.1-3 microg) did not affect Tb. The data demonstrate that delta-2 receptors are involved in the mediation of Tb effects, and deltorphin-II exerts its action directly on thermosensitive cells of the Preoptic Anterior Hypothalamus. Delta-1 opioid receptors do not appear to be involved in the control of body temperature.

  • Blockade of lipopolysaccharide-induced fever by a μ-opioid receptor-selective antagonist in rats
    European journal of pharmacology, 2000
    Co-Authors: Khalid Benamar, Ellen B Geller, Li Xin, Martin W Adler
    Abstract:

    The endogenous opioid system has been found to be involved in fever caused by pyrogens. In the present study, we have investigated the role of the mu-opioid receptor in the brain in fever induced by lipopolysaccharide. Rats were microinjected with 1 microg of the mu-opioid receptor-selective antagonist, cyclic D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH(2) (CTAP), into the Preoptic Anterior Hypothalamus. Thirty minutes later, lipopolysaccharide (50 microg/kg) was injected intraperitoneally (i.p.). CTAP reduced by 1 degrees C the fever induced by lipopolysaccharide. However, it did not affect lipopolysaccharide fever when it was given 3 h after lipopolysaccharide injection. These data indicate that mu-opioid receptors within the Preoptic Anterior Hypothalamus mediate the initiation of lipopolysaccharide fever and suggest that the opioid system is involved in the pathogenesis of fever in rats.

  • Substance P Release in the Rat Periaqueductal Gray and Preoptic Anterior Hypothalamus after Noxious Cold Stimulation: Effect of Selective Mu and Kappa Opioid Agonists
    The Journal of pharmacology and experimental therapeutics, 1997
    Co-Authors: Li Xin, Ellen B Geller, Lee-yuan Liu-chen, Chongguang Chen, Martin W Adler
    Abstract:

    Intracerebral microdialysis was used to measure changes in the extracellular level of substance P (SP) released from the periaqueductal gray (PAG) and the Preoptic Anterior Hypothalamus (POAH) of freely moving Sprague-Dawley rats after noxious cold stimulation. Artificial cerebrospinal fluid was perfused into the dialysis probe in the PAG or POAH and samples were collected every 30 min for 4 hr. SP-like immunoreactivity in the samples was measured by radioimmunoassay. In the PAG, SP base-line release was 0.43 ± 0.08 fmol/fraction. SP release was increased to 1.3 ± 0.4 fmol/fraction during the first collection period after noxious cold. Pretreatment with the selective mu opioid receptor agonist PL017 (0.8–3.4 nmol) or the kappa opioid receptor agonist dynorphin A1–17 (4.6–9.2 nmol), administered into the PAG by microinjection, produced dose-related inhibition of the cold-evoked SP release. Naloxone (10 mg/kg s.c.) administration 10 min before these opioid agonists reduced the inhibition of SP release. In the POAH, SP base-line release was 0.45 ± 0.06 fmol/fraction and noxious cold did not cause any significant change in SP release. Microdialysis of SP (271 fmol–271 pmol/μl/min, for 30 min) into the PAG, but not the POAH, induced dose-related analgesia (35–68% MPA) in the cold-water tail-flick test. However, microdialysis of SP into the POAH or PAG failed to induce any significant change in body temperature. These data suggest that 1) SP released from the PAG acts as a neuromodulator to transmit nociceptive information; 2) opioid receptor agonists can suppress this information by inhibiting SP release; 3) SP evoked by noxious cold may have a role in triggering the antinociceptive function of the PAG; and 4) SP does not appear to act as a neuromodulator for thermoregulatory responses in the POAH.

Jack A. Boulant - One of the best experts on this subject based on the ideXlab platform.

  • Cyclic GMP alters the firing rate and thermosensitivity of hypothalamic neurons.
    American journal of physiology. Regulatory integrative and comparative physiology, 2008
    Co-Authors: Chadwick Wright, Penny Wung Burgoon, Georgia A. Bishop, Jack A. Boulant
    Abstract:

    The rostral Hypothalamus, especially the Preoptic-Anterior Hypothalamus (POAH), contains temperature-sensitive and -insensitive neurons that form synaptic networks to control thermoregulatory respo...

  • Carbon dioxide and pH effects on temperature-sensitive and -insensitive hypothalamic neurons
    Journal of applied physiology (Bethesda Md. : 1985), 2006
    Co-Authors: Chadwick Wright, Jack A. Boulant
    Abstract:

    The Preoptic-Anterior Hypothalamus (POAH) controls body temperature, and thermoregulatory responses are impaired during hypercapnia. If increased CO2 or its accompanying acidosis inhibits warm-sens...

  • role of the Preoptic Anterior Hypothalamus in thermoregulation and fever
    Clinical Infectious Diseases, 2000
    Co-Authors: Jack A. Boulant
    Abstract:

    Lesion and thermal stimulation studies suggest that temperature regulation is controlled by a hierarchy of neural structures. Effector areas for specific thermoregulatory responses are located throughout the brain stem and spinal cord. The Preoptic region, in and near the rostral Hypothalamus, acts as a coordinating center and strongly influences each of the lower effector areas. The Preoptic area contains neurons that are sensitive to subtle changes in hypothalamic or core temperature. Preoptic thermosensitive neurons also receive a wealth of somatosensory input from skin and spinal thermoreceptors. In this way, Preoptic neurons compare and integrate central and peripheral thermal information. As a result of this sensory integration and its control over lower effector areas, the Preoptic region elicits the thermoregulatory responses that are the most appropriate for both internal and environmental thermal conditions. Thermosensitive Preoptic neurons are also affected by endogenous substances, such as pyrogens. By reducing the activity of warm-sensitive neurons and increasing the activity of cold-sensitive neurons, pyrogens cause fever, a state in which all thermoregulatory responses have elevated set-point temperatures.