Use-Dependent Regulation of GabaA Receptors

Barnes, Eugene M.

doi:10.1016/s0074-7742(08)60663-7

Cited by 98 publications

(62 citation statements)

References 97 publications

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“…PYY , cholecystokinin, amylin, and GLP-1 act at G protein coupled receptors. Numerous studies have demonstrated that prolonged exposure of G protein coupled receptors to agonists can induce receptor downregulation and tolerance (6,14,19,26,37). This likely explains why intermittent IV infusions of PYY(3-36) in our experimental model produced a sustained reduction in daily food intake, whereas continuous subcutaneous infusion of PYY produces only a transient suppression of feeding (31,39).…”

Section: Discussionmentioning

confidence: 84%

“…Thus the anorexic response to PYY(3-36) was sustained within and across experimental days with no apparent loss of sensitivity. Importantly, PYY(3-36) also reduced body weight gain across the 10-day period (Ϫ1.9 Ϯ 3.1 vs. 12.9 Ϯ 1.9 g in the vehicle-treated group, P Ͻ 0.001), and reduced carcass content of total fats, proteins, and water at the end of the 10-day period by 35,6, and 6%, respectively ( Table 1). The 15-g reduction in weight gain became a 27-g difference when body weights minus gut contents were compared, because gut contents were 55% larger in the PYY(3-36)-treated rats (Table 1).…”

Section: Effects Of 1-h IV Infusions Of Pyy(3-36) Every Other Hour Onmentioning

confidence: 93%

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Daily, intermittent intravenous infusion of peptide YY(3-36) reduces daily food intake and adiposity in rats

Chelikani

Haver²,

Reeve³

et al. 2006

American Journal of Physiology-Regulatory, Integrative and Comp

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reduces food intake and weight gain in rats when injected into the peritoneal cavity twice daily for 7 days. Numerous laboratories have failed to confirm that daily injections of PYY(3-36) decrease body weight. Continuous subcutaneous administration of PYY(3-36) by osmotic minipump has been reported to reduce daily food intake in rodents but only during the first 3-4 days of administration. Here we show the effects of different daily patterns of intravenous infusion of PYY(3-36) on food intake, body weight, and adiposity in rats tethered via infusion swivels to computercontrolled pumps. Measurement of food bowl weight recorded by computer every 20 s permitted daily assessment of the instantaneous effects of PYY(3-36) administration on food intake and meal patterns. One-hour intravenous infusions of PYY(3-36) at 30 pmol ⅐ kg Ϫ1 ⅐ min Ϫ1 every other hour for 10 days produced a sustained reduction in daily food intake of ϳ20% and decreased body weight and adiposity by 7 and 35%, respectively. Thus dosage pattern is critical for producing a sustained effect of PYY(3-36) on food intake and adiposity.gastrointestinal; body weight; body composition THE GASTROINTESTINAL SYSTEM plays an important sensing and signaling role in control of food intake and regulation of energy reserves (5). A growing number of peptide signals of gastric, intestinal, and pancreatic origin have been shown to inhibit short-term food intake when administered acutely to experimental animals and humans. These include cholecystokinin, amylin, glucagon-like peptide-1 (GLP-1), oxyntomodulin, peptide YY(3-36) ], pancreatic polypeptide, gastrinreleasing peptides (GRPs) GRP-27 and GRP-

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Section: Discussionmentioning

confidence: 84%

Section: Effects Of 1-h IV Infusions Of Pyy(3-36) Every Other Hour Onmentioning

confidence: 93%

Daily, intermittent intravenous infusion of peptide YY(3-36) reduces daily food intake and adiposity in rats

Chelikani

Haver²,

Reeve³

et al. 2006

American Journal of Physiology-Regulatory, Integrative and Comp

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“…9 Changes in the number or affinity of binding sites for GABA and benzodiazepine agonists have been demonstrated inconsistently after various benzodiazepine treatments. 2,5,9,26,50,68 Alternatively, a reduced allosteric interaction, i.e. decreased functional coupling, between GABA and benzodiazepine binding sites on native 9,17,23,51,64 and recombinant 32,50,72 GABA A receptors is a uniform finding.…”

Section: Discussionmentioning

confidence: 96%

Benzodiazepine-mediated regulation of α1, α2, β1–3 and γ2 GABAA receptor subunit proteins in the rat brain hippocampus and cortex

et al. 1999

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Abstract-Prolonged flurazepam exposure regulates the expression of selected (a1, b2, b3) GABA A receptor subunit messenger RNAs in specific regions of the hippocampus and cortex with a time-course consistent with benzodiazepine tolerance both in vivo and in vitro. In this report, the immunostaining density of six specific GABA A receptor subunit (a1, a2, b1-3 and g2) antibodies was measured in the hippocampus and cortex, among other brain areas, in slide-mounted brain sections from flurazepam-treated and control rats using quantitative computer-assisted image analysis techniques. In parallel with the localized reduction in a1 and b3 subunit messenger RNA expression detected in a previous study, relative a1 and b3 subunit antibody immunostaining density was significantly decreased in flurazepam-treated rat hippocampal CA1, CA3 and dentate dendritic regions, and in specific cortical layers. Quantitative western blot analysis showed that b3 subunit protein levels in crude homogenates of the hippocampal dentate region from flurazepam-treated rats, an area which showed fairly uniform decreases in b3 subunit immunostaining (16-21%), were reduced to a similar degree (18%). The latter findings provide independent support that relative immunostaining density may provide an accurate estimate of protein levels. Consistent with the absence of the regulation of their respective messenger RNAs immediately after ending flurazepam administration, no changes in the density of a2, b1 or b2 subunit antibody immunostaining were found in any brain region. g2 subunit antibody staining was changed only in the dentate molecular layer.The selective changes in GABA A receptor subunit antibody immunostaining density in the hippocampus suggested that a change in the composition of GABA A receptors involving specific subunits (a1 and b3) may be one mechanism underlying benzodiazepine anticonvulsant tolerance. ᭧ 1999 IBRO. Published by Elsevier Science Ltd.Key words: tolerance, flurazepam, quantitative immunohistochemistry, dentate gyrus, limbic system, CA1 pyramidal cells.Although effective anxiolytics and hypnotics, the clinical use of benzodiazepines as anticonvulsants is limited by tolerance development during prolonged administration. A large body of evidence has indicated that benzodiazepine tolerance is related to a reduction in GABA A receptor-mediated fast inhibitory synaptic transmission (for reviews see Refs 2 and 27). The native GABA A receptor is a pentamer composed of combinations of homologous proteins derived from five subunit families with multiple variants (a1-6, b1-4, g1-3, d1 and e1). 8,11,34 The GABA A receptor macromolecule contains binding domains for GABA and several allosteric modulators, including a well-characterized benzodiazepine binding site. 59Benzodiazepines potentiate GABA A receptor-mediated inhibitory function by increasing the opening probability of the integral Cl Ϫ channel, 52,62 and may increase Cl Ϫ channel conductance. 13Although the synaptic mechanisms mediating benzodiazepine tolerance have not been...

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“…Receptor internalization is of major importance for receptor recycling and is an important determinant for the availability of functionally active membrane-bound receptors (Calkin and Barnes, 1994;Barnes, 1996;Miranda and Barnes, 1997). For example, chronic administration of benzodiazepines induces internalization of the GABA A receptor (Tehrani and Barnes, 1997).…”

Section: Discussionmentioning

confidence: 99%

Antidepressants and Antipsychotic Drugs Colocalize with 5-HT₃Receptors in Raft-Like Domains

Eisensamer¹,

Uhr²,

Meyr³

et al. 2005

J. Neurosci.

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Use-Dependent Regulation of GabaA Receptors

Cited by 98 publications

References 97 publications

Daily, intermittent intravenous infusion of peptide YY(3-36) reduces daily food intake and adiposity in rats

Daily, intermittent intravenous infusion of peptide YY(3-36) reduces daily food intake and adiposity in rats

Benzodiazepine-mediated regulation of α1, α2, β1–3 and γ2 GABAA receptor subunit proteins in the rat brain hippocampus and cortex

Antidepressants and Antipsychotic Drugs Colocalize with 5-HT₃Receptors in Raft-Like Domains

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Use-Dependent Regulation of GabaA Receptors

Cited by 98 publications

References 97 publications

Daily, intermittent intravenous infusion of peptide YY(3-36) reduces daily food intake and adiposity in rats

Daily, intermittent intravenous infusion of peptide YY(3-36) reduces daily food intake and adiposity in rats

Benzodiazepine-mediated regulation of α1, α2, β1–3 and γ2 GABAA receptor subunit proteins in the rat brain hippocampus and cortex

Antidepressants and Antipsychotic Drugs Colocalize with 5-HT3Receptors in Raft-Like Domains

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Antidepressants and Antipsychotic Drugs Colocalize with 5-HT₃Receptors in Raft-Like Domains