5-HT1b receptors in an animal model of depression.
After exposure to a 0.8 mA course of uncontrollable shocks, Sprague-Dawley rats can be differentiated into two distinct groups defined in term of their performance in a shock escape paradigm. Learned helpless (LH) rats do not learn to escape a controllable shock while non-helpless (NLH) rats learn this response as quickly as naive controls (NC) rats do. The current experiments were designed to extend our studies of 5-HT receptors in these three groups of rats. The major finding in the present study concerned post-synaptic 5-HT receptor effects in the cortex, hippocampus, septum and hypothalamus of LH rats. These included an up regulation of 5-HT1b receptors in the cortex, hippocampus and septum in LH rats. In contrast, 5-HT1b receptors in the hypothalamus of LH rats were down-regulated. These results implicate serotonergic mechanisms in the behavioral deficit caused by uncontrollable shock with a limbic-hypothalamic circuit serving as a center for adaptation to stress.
Edwards
E
E
Department of Psychiatry and Behavioral Science, State University of New York at Stony Brook 11794-8101.
Harkins
K
K
Wright
G
G
Henn
F A
FA
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002540:Cerebral Cortex / Q000378:metabolism; D003863:Depression / Q000378:metabolism / Q000503:physiopathology*; D004195:Disease Models, Animal; D004597:Electroshock; D004924:Escape Reaction; D006380:Helplessness, Learned; D006624:Hippocampus / Q000378:metabolism; D007031:Hypothalamus / Q000378:metabolism; D007700:Kinetics; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011985:Receptors, Serotonin / Q000378:metabolism*; D012016:Reference Values
D011985:Receptors, Serotonin