Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9416561 | Brain Research | 2005 | 14 Pages |
Abstract
This study examined the distribution of 5-HT-immunoreactive perikarya (5-HT-IRp) and the effects of local injections of 8-OH-DPAT into 5-HT-IRp-containing pontine and mesencephalic regions on feeding and drinking behaviors in free-feeding pigeons. When infused into the midline 5-HT-IRp-containing areas, 8-OH-DPAT (6.1 nmol) reliably elicited drinking and, to a lesser extent, feeding responses during the first hour after injection. These responses were significantly higher than the ingestive indexes observed (1) after vehicle (ascorbic acid 0.1%, 200 nl) injections at the same sites and (2) after 8-OH-DPAT injections into adjacent sites devoid of 5-HT-IRp. Increases in drinking were proportionally higher than those observed in feeding and a significant negative correlation was observed between water and food after midline 8-OH-DPAT injections. Similar dipsogenic responses were observed after injections of different 8-OH-DPAT doses (0.6, 2.0, and 6.1 nmol). Pretreatment with local injections of p-MPPI (an antagonist of 5-HT1A receptors) attenuated the ingestive responses evoked by 8-OH-DPAT injections. Injections of 8-OH-DPAT into lateral 5-HT-IRp-containing sites evoked only inconsistent and weak ingestive responses. These results indicate that 5-HT1A receptor-mediated circuits located in the midline superior raphe system of the pigeon may play an important role in mechanisms controlling water intake, similar to that observed in mammals.
Keywords
ANNnBORfasciculus longitudinalis medialisNIIISubstantia grisea centralisSCVEpendymaAVTMPVGCTFRMPAPFRLFLMSCDTPCBCDNIVRPOAvianaqueduct4th ventricleNucleus ruberIngestive behaviorsOculomotor nerveNeural Basis of BehaviorLocCerebellumWater intakefood intakeEdinger–Westphal nucleusraphe nucleinucleus of the basal optic rootnucleus reticularis pontis oralis
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Authors
Luciane P.N. Häckl, Graciela de Oliveira Richter, Moacir Serralvo Faria, Marta A. Paschoalini, José Marino-Neto,