An excitatory influence of dorsolateral pontine structures on urinary bladder motility in the rat.

The effects of electrical stimulation of dorsolateral pontine structures on urinary bladder motility have been compared with those of microinjection of an excitatory amino acid, DL-homocysteic acid (DLH), which is believed to activate neuronal cell bodies but not axons. Increases in the intravesical pressure (IVP), indicative of urinary bladder contractions, were observed following low intensity (less than 50 microA) electrical stimulation in the brachium conjunctivum (BC) and the surrounding parabrachial nucleus (PBN). In contrast, increases in IVP evoked by DLH were observed only after its injection into a localised area just dorsal to the BC, in the region of the lateral parabrachial nucleus. These results suggest that cell bodies of neurones with an excitatory influence on the urinary bladder are located in restricted regions of the PBN, dorsal to the BC.