Effects of psychotropic drugs microinjected into the hypothalamus on muricide, catalepsy and cortical EEG in OB rats.

In order to elucidate the mechanism of anti-muricide action of psychotropic drugs in the brain, the present study examined influences of these drugs microinjected into the hypothalamus on muricide. Inhibition of muricide by chlorpromazine (CPZ) was found both in the lateral preoptic area (1-POA) and the posterior part of the lateral hypothalamus (p-LH), and that by chlordiazepoxide was seen only the mammillary body. These effects were accompanied by a drowsiness of cortical EEG. Anti-muricide action of tricyclic antidepressants was found in p-LH. The effect was not accompanied by EEG drowsiness. Effects of atropine injected into the hypothalamus on muricide and cortical EEG were similar to those of the antidepressants. Norepinephrine and serotonin did not show selective muricide-suppression. Although either CPZ in 1-POA and p-LH or the antidepressants in p-LH showed cataleptogenic effect, these effects did not appear related to anti-muricide action. The relationship between the anti-muricide action of psychotropic drugs and the physiological functions of the brain was discussed in comparison with these systemic administrations.