We have modeled some aspects of electroconvulsive therapy (ECT) in rats. In
addition to sham-treated controls, one group received two electroconvulsiv
e (ECS) current-doses at grand mal seizure threshold. Two more groups recei
ved three additional ECSs at two higher current-doses. Only the two suprath
reshold groups showed significant antidepressant (AD) effects in the forced
-swim test, but all three seizure groups showed significant increases in TR
H and related peptides in anterior cortex (AC), pyriform cortex (PYR), amyg
dala/entorhinal cortex (AY), and hippocampus (HC). In motor cortex (MC), TR
H appeared to be increased only in the lower dose suprathreshold ECS condit
ion. No condition increased TRH in striatum (STR). These results fell short
of directly implicating limbic TRH in AD effects, but in HC, MC, and STR,
correlations of peptide levels with individual swim scores raise the possib
ility that this peptidergic system might be involved in motor as well as af
fective functions. Other peptides related to TRH might also be implicated i
n affective regulation and antidepressant effects. (C) 1999 Elsevier Scienc
e Inc.