[The effects of substance P and capsaicin on synaptic transmission in the peripheral reflex pathways of the rat caudal mesenteric ganglion].

Peripheral nerve pathways in the caudal mesenteric ganglion of the rat were found. They preserve synaptic transmission after degeneration of preganglionic nerve fibres. To find the effects of substance P (SP) and capsaicin, the SP antagonist, on the synaptic transmission in peripheral reflex pathways of the caudal mesenteric ganglion rats were investigated using extracellular recording of action potentials from the ganglion nerves. Perfusion of the ganglion by solution containing SP (5 x 10(-7) and 1 x 10(-8) mol/l), facilitated the transmission, while capsaicin (5 x 10(-5) mol/l) inhibited it. The inhibitory effect grew at high-frequency stimulation of peripheral nerves.