Central amygdalar nucleus treated with orexin neuropeptides evoke differing feeding and grooming responses in the hamster.
Interaction of the orexinergic (ORXergic) neuronal system with the excitatory (glutamate, l-Glu) or the inhibitory (GABA) neurosignaling complexes evokes major homeostatic physiological events. In this study, effects of the two ORXergic neuropeptides (ORX-A/B) on their receptor (ORX-2R) expression changes were correlated to feeding and grooming actions of the hibernating hamster (Mesocricetus auratus). Infusion of the central amygdala nucleus (CeA) with ORX-A caused hamsters to consume notable quantities of food, while ORX-B accounted for a moderate increase. Interestingly the latter neuropeptide was responsible for greater frequencies of grooming with respect to both controls and the hamsters treated with ORX-A. These distinct behavioral changes turned out to be even greater in the presence of l-Glu agonist (NMDA) while the α1 GABAA receptor agonist (zolpidem, Zol) greatly reduced ORX-A-dependent feeding bouts. Moreover, ORX-A+NMDA mainly promoted greater ORX-2R expression levels with respect to ORX-A-treated hamsters while ORX-B+Zol was instead largely responsible for a down-regulatory trend. Overall, these features point to CeA ORX-2R sites as key sensory limbic elements capable of regulating eating and grooming responses, which may provide useful insights regarding the type of molecular mechanism(s) operating during feeding bouts.
Comparative Neuroanatomy Laboratory, Biology, Ecology & Earth Science Department (DiBEST), University of Calabria, Ponte Pietro Bucci, 87030 Arcavacata di Rende, Cosenza, Italy. Electronic address: raffaella.alo@unical.it.
Raffaella
R
Alò
Comparative Neuroanatomy Laboratory, Biology, Ecology & Earth Science Department (DiBEST), University of Calabria, Ponte Pietro Bucci, 87030 Arcavacata di Rende, Cosenza, Italy.
Ennio
E
Avolio
Comparative Neuroanatomy Laboratory, Biology, Ecology & Earth Science Department (DiBEST), University of Calabria, Ponte Pietro Bucci, 87030 Arcavacata di Rende, Cosenza, Italy.
Maria
M
Mele
Molecular Oncology Laboratory, Experimental and Clinical Medicine Department, University Magna Graecia of Catanzaro, 88100 Catanzaro, Italy.
Anna
A
Di Vito
Comparative Neuroanatomy Laboratory, Biology, Ecology & Earth Science Department (DiBEST), University of Calabria, Ponte Pietro Bucci, 87030 Arcavacata di Rende, Cosenza, Italy.
Marcello
M
Canonaco
D000818:Animals; D066274:Central Amygdaloid Nucleus / Q000187:drug effects / Q000378:metabolism*; D006224:Cricetinae; D005247:Feeding Behavior / Q000187:drug effects / Q000502:physiology*; D058785:GABA-A Receptor Agonists / Q000494:pharmacology; D006120:Grooming / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008647:Mesocricetus / Q000378:metabolism / Q000502:physiology*; D016202:N-Methylaspartate / Q000378:metabolism; D064446:Orexin Receptors / Q000187:drug effects / Q000378:metabolism*; D000068797:Orexins / Q000494:pharmacology / Q000502:physiology*
D058785:GABA-A Receptor Agonists; D064446:Orexin Receptors; D000068797:Orexins; D016202:N-Methylaspartate
Amygdala; Feeding behaviors; GABA(A) receptor; NMDA; Orexin