Central neural control of the lower urinary tract.

The lower urinary tract has two main functions, the storage and periodic elimination of urine, which are regulated by a complex neural control system in the brain and spinal cord. This neural system exhibits switch-like patterns of activity that are generated by visceral reflex circuits, some of which are under voluntary control. Experimental studies in animals indicate that the micturition reflex is mediated by a spinobulbospinal pathway passing through a coordination centre (the pontine micturition centre) located in the rostral brainstem. This reflex pathway is, in turn, modulated by higher centres in the cerebral cortex which are presumably involved in the voluntary control of micturition. Several neurotransmitters (including GABA, opioid peptides and glutamic acid) appear to have a role in the central pathways controlling micturition. Since pharmacological manipulation of putative inhibitory transmitter mechanisms increases bladder activity and decreases bladder capacity it is possible that similar changes induced by pathological conditions may underlie bladder dysfunctions occurring in patients with neurogenic urinary incontinence. Further study of these neurotransmitter systems may yield new therapeutic approaches for the treatment of hyperactive bladder disorders.