Developmental Changes in the Expression of TRPV1 Channels in Autonomic Nervous System Neurons

The expression of TRPV1 channels in neurons in sympathetic and afferent ganglia in rat pups of different ages (neonatal, aged 10, 20, 30, 60, and 180 days) were studied immunohistochemically. The results showed that most neurons in the sensory ganglion of the vagus nerve and the spinal ganglia contain TRPV1 channels from birth. During ontogeny, there was a small increase in the proportion of cells containing TRPV1 channels in the spinal ganglia to day 20 of life. The proportion of TRPV1-positive neurons in neurons in the sensory ganglion of the vagus nerve showed no significant developmental change. The sensory ganglion of the vagus nerve all age groups showed higher proportions of TRPV1-immunoreactive neurons than spinal ganglia. In the sympathetic ganglia of neonatal animals, the vast majority of neurons contained TRPV1 channels, after which the proportion of TRPV1-positive neurons decreased sharply, such that there were only occasional neurons containing this type of channel by age 20 days. The final proportion of TRPV1-containing neurons, comparable with that in adults, was reached by the end of the first month of life.