抄録
The neurons in and around the micturition center, the Barrington’s nucleus, show several types of firing pattern in relation with bladder contraction; (1) those which increase their firing in advance or in synchronous with the change in bladder pressure (type E) and (2) those which fire in reverse to the change in bladder pressure (Type I). These neurons are considered to have a crucial role in the regulation of bladder contraction. However, the neural input from the urinary bladder to these neurons are scarcely known. Using urethane anesthetized rats, single neuronal activity in and around the micturition center was recorded through glass pipette electrode while the urinary bladder is spontaneously contracting. After identifying the neuronal type, response of these neurons to bladder extension was examined by infusion of saline (0.2–0.3 ml) into the bladder. In responding to bladder extension, most of the type E neurons increase their firing, while in type I neurons, some of them increase their firing rate, and others reduce it. These findings suggest that, type E neurons receive excitatory inputs, and type I neurons receive both excitatory and/or inhibitory inputs from the dilating bladder. [Jpn J Physiol 55 Suppl:S193 (2005)]
