GABAA and GABAB agonist microinjections into medial accumbens shell increase feeding and induce anxiolysis in an animal model of anxiety.
This study investigated the effect of GABAA (muscimol, MUSC) and GABAB (baclofen, BACL) agonist receptors microinjected into medial accumbens shell on feeding and the level of fear in free-feeding rats submitted to the elevated plus-maze (EPM), an animal model of anxiety. Bilateral microinjections of either MUSC (128 pmol/0.2 microl/side) or BACL (128 and 256 pmol/0.2 microl/side) induced an anxiolytic-like effect since they decreased the occurrence of risk assessment, a defensive behaviour positively correlated with the animal anxiety level. Bilateral BACL microinjection (128 pmol), but not MUSC, also increased the head-dipping frequency over the open arms of the EPM, another representative behaviour of anxiety, but negatively correlated with it. In addition to anxiolysis, the present study also showed that the microinjection of MUSC and BACL agonists into rostral sites of the medial Acb shell (AP, +1.2 to +1.6) increased food intake significantly whereas drinking behaviour kept unchanged. Both doses of MUSC and BACL also decreased feeding latency. BACL but not MUSC dose-dependently increased food length. The data indicated a putative role of GABA receptors (especially GABAB) in the medial Acb shell for anxiety modulation in rats.
Lopes
Ana Paula Fraga
AP
Department of Physiological Sciences, Centre of Biological Sciences, Federal University of Santa Catarina 88, 040-900 Florianópolis, SC, Brazil.
da Cunha
Isabel Cristina
IC
Steffens
Sergio Murilo
SM
Ferraz
Adriana
A
Vargas
Juliano Cordova
JC
de Lima
Thereza Christina Monteiro
TC
Neto
José Marino
JM
Faria
Moacir Serralvo
MS
Paschoalini
Marta Aparecida
MA
D000704:Analysis of Variance; D000818:Animals; D001007:Anxiety / Q000188:drug therapy* / Q000503:physiopathology; D001418:Baclofen / Q000008:administration & dosage*; D001522:Behavior, Animal / Q000187:drug effects; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005247:Feeding Behavior / Q000187:drug effects*; D005260:Female; D018755:GABA Agonists / Q000008:administration & dosage*; D018782:Maze Learning / Q000187:drug effects; D008845:Microinjections / Q000379:methods; D009118:Muscimol / Q000008:administration & dosage*; D009714:Nucleus Accumbens / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D011930:Reaction Time / Q000187:drug effects
D018755:GABA Agonists; D009118:Muscimol; D001418:Baclofen