Evidence for an action of heptaminol hydrochloride (Hept‐a‐myl^R) on the central nervous system based on an increase in intracranial self‐stimulation behavior in the mouse

Abstract

Durantou, F., P. Cazala, and B. Pourrias: Evidence for an action of heptaminol hydrochloride (Hept-a-mylR) on the central nervous system based on an increase in intracranial self-stimulation behavior in the mouse. Drug Dev. Res. 20:465-472, 1990.The effects of intraperitoneal injections of heptaminol hydrochloride (Hept-a-mylR) on intracranial self-stimulation (ICSS) in the lateral hypothalamus (LH) were studied in BALB/c mice. In a first experiment, performed in a lever press box, we observed that ICSS induced by brief (0.2 sec) electrical stimulation was enhanced by heptaminol. However, at the two doses administered (34.6 and 60 mg/kg), increases of the lever-pressing rate were observed only in animals showing high levels of performance before the treatment. In a second experiment, mice were trained in a shuttle-box to initiate and terminate a continuous stimulation of the LH. In animals showing a weak approach response before the treatment, heptaminol induced a significant reduction of approach latency but only at the dose of 60 mglkg. In contrast, animals showing a strong approach response appeared more sensitive to heptaminol since a reduction of approach latency was observed at the two doses administered. No concomitant modification of escape latency was observed. These results suggest 1) that heptaminol modulates activity of certain neuronal mechanisms involved in ICSS regulation and 2) that a relationship exists between the reactivity to heptaminol and the sensitivity of hypothalamic sites to electrical stimulation.