Clarification of transmission mechanism of urinary sensation in pontine micturition center and central effect of drugs for voiding dysfunction.

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We performed electrophysiological studies in order to clarify the relationship between the pontine micturition center and micturition. A catheter was inserted into the bladder and saline was injected until spontaneous contraction was induced. A glass pipette microelectrode was inserted through the cerebellum. Single neural activity was recorded in the mesopontine tegmentum including the Barrington's nucleus and simultaneously its precise timing in relation to bladder contraction was observed. Three types of neuron were distinguished ; those which fired only prior to the start of contraction (E1), those whose firing started shortly prior to and was maintained during contraction (E2), and those whose firing, was strongly suppressed during contraction (I). The results showed that direct neural signals to induce bladder contraction might arise from the Barrington's nucleus. The neurons were classified into three types with different functional roles.In order to clarify the effects of drugs for voiding dysfunction on the micturition center, an anticholinergic drug (oxybutynin hydrochloride) and a tricyclic antidepressant (clomipramine hydrochloride) were administered intravenously during the recording of E1 and E2 neurons. With the administration of oxybutynin, neural firing increased in accordance with the suppression of bladder contraction. On the other hand, neural firing decreased with the administration of clomipramine. From these results, it seemed that oxbutynin and clomipramine had similar peripheral effects and different central effects. In order to clarify the effects of desmopressin on the micturition center, it was administered intravenously and intraventriculary. With the administration, neurons were observed in which the firing changed in accordance with the suppression of bladder contraction. From these results, the possibility of the central effect of desmopressin was suggested