Nobuya Ogawa

Mouse-killing behavior (muricide) induced by Δ9-tetrahydrocannabinol in the rat

Abstract Natural Δ 9 -tetrahydrocannabinol (THC) was found to induce a characteristic mouse-killing behavior (muricide) in rats upon chronic administration. In the rat housed individually, this muricide developed even on the first day of administration, and continued for a long period of time even after withdrawal of the drug.

Effect of bilateral olfactory bulbectomy on discrimination avoidance conditioning in rats.

Studies were made with the two-way shuttle box method on the acquisition of discrimination avoidance learning by olfactory bulbectomized rats in relation to changes in emotional behavior. Bulbectomized rats showed a marked increase in locomotor activity, with accompanying augmentation of the reactivity and the appearance of muricidal behavior. Initially, the bulbectomized rats showed elevated conditioned avoidance responses to both the CS+ and the CS-. In later stages, there was a continued slow increase in responses to the CS+ accompanied by a decrease in responses to the CS-, until responses to both stimuli were only slightly elevated above the levels shown by control rats. This result suggests that olfactory bulbectomy does not affect discrimination ability itself, but the impairment of discrimination during the initial stages is resulted from hyperemotionality induced by olfactory bulbectomy.

Effects of psychotropic drugs on discrimination conditioning in olfactory bulbectomized rats.

In the acquisition process of discrimination avoidance conditioning, bilateral olfactory bulbectomized rats showed poor discrimination conditioning since both the avoidance responses to positive conditioned stimuli (CS) and the incorrect responses to negative CS increased. The effects of various psychotropic drugs upon this poor discrimination conditioning were examined. Chlordiazepoxide 5 mg/kg, IP, produced an increase in the avoidance responses with simultaneous decrease in the incorrect responses, thus making the discrimination possible. Chlorpromazine 2 mg/kg, IP, worsened the discrimination by decreasing both the avoidance and incorrect responses as compared with saline-treated rats. Amitriptyline 10 mg/kg, IP, decreased the incorrect responses without affecting the avoidance responses, thus making the discrimination possible. Methamphetamine 0.5 mg/kg, IP, increased both the avoidance and incorrect responses resulting in poor discrimination conditioning. From these results, it was found that the poor discrimination conditioning of O.B. rats was improved by psychotropic drugs like chlordiazepoxide and amitriptyline.

Effect of bilateral septal lesions on discrimination avoidance conditioning in rats

Studies were performed, using the two-way shuttle box method, on the acquisition of discrimination avoidance by rats with bilateral lesions of the septum (septal rats) in relation to changes in emotional behavior. Septal rats exhibited hyperreactivity immediately after the lesions were made: their startle, struggle and vocalization responses to stimuli were markedly increased. These hyperemotional responses, however, decreased and returned to the normal level 7 days after surgery. Initially, the septal rats showed elevated conditioned avoidance responses to both the CS+ and the CS-. In later stages, their responses to the CS+ showed progressive and gradual increase, accompanied by a decrease in responses to the CS-, until responses to both stimuli were only slightly elevated above the level of control rats. These results suggest that bilateral lesions of the septum do not affect discrimination ability itself. The impairment of discrimination avoidance during the initial stages may result from the transient impairment of the discrimination acquisition process.

Clinical course of peptic ulcer and the effect of pharmacotherapy

SummaryComparative clinical trials were conducted by the double-blind technique in a series of 302 cases of gastric ulcer at fifteen medical institutions in order to investigate the clinical course of peptic ulceration and the effect of pharmacotherapy on it, using N-acetyl-L-glutamine aluminum complex (KW) as test drug and basic aluminum sucrose sulfate (UL) as reference drug as well as an inactive placebo of lactose (PL) with the results as follows:In 12 weeks of treatment with inactive placebo, a higher cure rates were noted in inpatients than in outpatients, and in patients with ulceration in the corpus ventriculi than in those with ulceration at the angulus. The overall evaluation of therapeutic responses indicated that, both KW and UL were significantly superior in efficacy to placebo in 12 weeks of therapy. These two medicaments displayed different modes of efficacy, possibly reflecting their different mechanisms of pharmacologic action. The efficacy of the medicaments was particularly superior in outpatients and patients with peptic ulceration at the gastric angle both of which showed lower rates of response to placebo.