DESMOPRESSIN AND VASOPRESSIN INCREASE LOCOMOTOR-ACTIVITY IN THE RAT VIA A CENTRAL MECHANISM - IMPLICATIONS FOR NOCTURNAL ENURESIS

Purpose: Nocturnal enuresis is characterized by nocturnal urine volume s exceeding bladder capacity and by inability to wake up to the stimul us of a full bladder. Desmopressin (DDAVP) is believed to be efficient in treating nocturnal enuresis by reducing nocturnal urine production . However, clinical observations indicate an additional mode of action since the drug appears to modify sleep architecture, apparently impro ving the patient's ability to awaken to the stimulus of a full bladder . Because of this, a possible arousing effect of DDAVP was studied. Ma terials and Methods: The tentative ability of DDAVP and the endogenous hormone vasopressin (AVP) to produce locomotor stimulation in resting rats after both intracerebroventricular and subcutaneous administrati on was used as an animal model of arousal. In addition brain monoamine biochemistry was analyzed. Results: The intracerebroventricular injec tion of AVP (0.1 and 1 mu g.) and the intracerebroventricular (0.1, 1, 10 and 100 mu g.) and subcutaneous (90 and 180 mu g.) injections of D DAVP were both associated with a significant increase in the locomotor activity of the animals compared with controls. The biochemical analy sis of cerebral monoamines indicated that DDAVP lowers brain dopamine levels after both types of administration. Conclusions: These results suggest that DDAVP exerts a stimulatory effect in the CNS, which is al so observed after peripheral administration. There are also indication s for an increase in central dopamine turnover which could explain the registered increase in locomotor activity.