Excitatory/inhibitory equilibrium of the central amygdala nucleus gates anti-depressive and anxiolytic states in the hamster.
Several studies have pointed to the amygdala as a main limbic station capable of regulating different stressful states such as anxiety and depression. In this work it was our intention to determine the role of the central amygdala nucleus (CeA) on the execution of either anxiolytic and/or anti-depressant behaviors in the hibernating hamster (Mesocricetus auratus) via infusion of CeA with the antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) specific for α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR) plus the specific agonist for α4 GABAAR i.e. 4,5,6,7-tetrahydroisoxazolo(5,4-c)pyridin-3-ol (THIP). Treatment with CNQX appeared to mainly prompt anti-depressant effects as shown by the achievements of swimming feats during forced swim test while THIP prevalently accounted for evident bouts of climbing when exposed to the same test. Moreover, even in the presence of the concomitant administration of both of these compounds, hamsters continued to spend more time in swimming despite this significant behavioral effect resulted to be numerically reduced for hamsters treated with only the α4 GABAAR agonist. Conversely, when these animals were tested in elevated plus maze (EPM), THIP tended to mostly favor anxiolytic activities as exhibited by stressed animals spending more time entering and remaining in EPM open arms. It was interesting to note that behavioral changes induced by both drugs appeared to be also responsible for glutamate receptor (GluR) expression differences as indicated by CNQX favoring an evident up-regulation of GluR2-containing neurons whereas THIP induced an up-regulation, this time of GluR1-containing neurons. Overall, the anti-depressant role of CNQX seems to be mostly attributed to elevated GluR2 levels while an anxiolytic-like effect of THIP was correlated to high GluR1values thereby proposing distinct GluRs as useful therapeutic sites against degenerative diseases such as depression-like behaviors.
Comparative Neuroanatomy Laboratory, Biology, Ecology & Earth Science Department (DiBEST), University of Calabria, Ponte Pietro Bucci 4B, 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 4B, 87030 Arcavacata di Rende, Cosenza, Italy; Health Center srl, Biomedical and Nutritional Center, via Sabotino 66, 87100 Cosenza, Italy.
Ennio
E
Avolio
Comparative Neuroanatomy Laboratory, Biology, Ecology & Earth Science Department (DiBEST), University of Calabria, Ponte Pietro Bucci 4B, 87030 Arcavacata di Rende, Cosenza, Italy.
Maria
M
Mele
Comparative Neuroanatomy Laboratory, Biology, Ecology & Earth Science Department (DiBEST), University of Calabria, Ponte Pietro Bucci 4B, 87030 Arcavacata di Rende, Cosenza, Italy.
Francesca
F
Storino
Health Center srl, Biomedical and Nutritional Center, via Sabotino 66, 87100 Cosenza, Italy.
Alessia
A
Canonaco
Comparative Neuroanatomy Laboratory, Biology, Ecology & Earth Science Department (DiBEST), University of Calabria, Ponte Pietro Bucci 4B, 87030 Arcavacata di Rende, Cosenza, Italy.
Antonio
A
Carelli
Comparative Neuroanatomy Laboratory, Biology, Ecology & Earth Science Department (DiBEST), University of Calabria, Ponte Pietro Bucci 4B, 87030 Arcavacata di Rende, Cosenza, Italy.
Marcello
M
Canonaco
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000008:administration & dosage; D000679:Amygdala / Q000187:drug effects / Q000503:physiopathology*; D000818:Animals; D001007:Anxiety / Q000188:drug therapy / Q000235:genetics / Q000503:physiopathology*; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D006224:Cricetinae; D003863:Depression / Q000188:drug therapy / Q000235:genetics / Q000503:physiopathology*; D018691:Excitatory Amino Acid Antagonists / Q000008:administration & dosage; D058785:GABA-A Receptor Agonists / Q000008:administration & dosage; D007555:Isoxazoles / Q000008:administration & dosage; D008297:Male; D008647:Mesocricetus; D008845:Microinjections; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018091:Receptors, AMPA / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D013312:Stress, Physiological
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D018691:Excitatory Amino Acid Antagonists; D058785:GABA-A Receptor Agonists; D007555:Isoxazoles; D012333:RNA, Messenger; D018091:Receptors, AMPA; C015542:gaboxadol; C104722:glutamate receptor ionotropic, AMPA 2
AMPAR; Central amygdala nucleus; Forced swim test; GABA(A)R