Passive avoidance learning involves alpha2-noradrenergic receptors in a day old chick.
Day-old chicks were trained on one-trial passive avoidance task, using methyl-anthranilate (MeA) as an aversive substance. Bilateral pharmacological manipulation of the intermediate hyperstriatum ventrale was performed by intracerebral application of an alpha2-noradrenergic agonist, clonidine (5 microM), or an antagonist, rauwolscine (300 microM). Only rauwolscine application (pre- or post-training) induced significant memory impairment. Quantitative receptor autoradiography was used to determine the kinetic properties of the binding sites for [3H]clonidine or [3H]rauwolscine in MeA-trained or water-trained (control) chicks, in forebrain areas known to be involved in avoidance learning. Scatchard analysis revealed that MeA-training resulted in a significant bilateral upregulation in the number of [3H]rauwolscine binding sites (Bmax) in the area of hyperstriatum ventrale. These findings suggest the importance of activation of alpha2-noradrenergic receptors in aversive learning in chicks.
Department of Biology, University of Crete, Heraklion, Greece.
A
A
Stamatakis
M G
MG
Stewart
C R
CR
Dermon
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D001345:Autoradiography; D001362:Avoidance Learning / Q000187:drug effects / Q000502:physiology*; D002645:Chickens; D003000:Clonidine / Q000494:pharmacology*; D007839:Functional Laterality; D007276:Injections, Intraventricular; D016548:Prosencephalon / Q000187:drug effects / Q000378:metabolism; D018341:Receptors, Adrenergic, alpha-2 / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D015016:Yohimbine / Q000494:pharmacology*
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D018341:Receptors, Adrenergic, alpha-2; D015016:Yohimbine; D003000:Clonidine