BEHAVIOURAL CHANGES INDUCED IN CONSCIOUS MICE BY INTRACEREBROVENTRICULAR INJECTION OF CATECHOLAMINES, ACETYLCHOLINE AND 5‐HYDROXYTRYPTAMINE

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Abstract
A simple method of injecting soluble substances into the lateral ventricle of the brain of the conscious mouse is described. The effect of various doses of noradrenaline, dopamine, acetylcholine, 5‐hydroxytryptamine given into the right lateral brain ventricle were tested on locomotor and exploratory activities of mice. Noradrenaline in a dose of 0.1 μg increased locomotor activity. This effect was prevented by phenoxybenzamine but not by propranolol. Higher doses of noradrenaline (1 or 10 μg) decreased locomotor and exploratory activities. Propranolol but not phenoxybenzamine abolished these effects. Dopamine (0.1 or 1 μg) increased locomotor activity. The higher doses also induced tremor. The highest dose of dopamine tested (10 μg) elicited stereotypical behaviour. All the behavioural phenomena induced by 0.1 μg and 10 μg of dopamine were blocked by pimozide. Acetylcholine (1 and 10 μg) and 5‐hydroxytryptamine (1 μg) inhibited locomotor and exploratory activity. The effects of 1 and 10 μg of acetylcholine were abolished by atropine (5 mg/kg i.p.). Methysergide (5 mg/kg i.p.) had no influence on the effects of 5‐hydroxytryptamine (1 μg).