Modaline, 2-methyl-3-piperidinopyrazine derivative, was found to inhibit monoamine oxidase (MAO) (1, 2) and showed therapeutic anti-depressant activity (3). This compound potentiated convulsions induced by tryptamine and hyperthermia induced by dopa similar to other MAO inhibitors (2). Moreover, it also antagonised reserpine induced hypothermia like imipramine (2). Gylys et al. (4) showed that peripheral administration of modaline resulted in hypotension due to ganglionic blockade. Both imipramine and MAO inhibitors viz. pheniprazine and iproniazid were found to inhibit the excitability of the hypothalmic and brain stem vasomotor loci (5, 6). On the other hand, modaline potentiated the facilitation of monosynaptic spinal reflexes induced by stimulation of brain stem reticular formation (7). Therefore, investigation of the central vasomotor effects of modaline after injection into the lateral cerebral ventricle in dogs was carried out.