M 3 cholinergic receptors are involved in postnatal development of cholinergic regulation of cardiac activity in rats

摘要

We studied the role of M 3 cholinergic receptors in the regulation of cardiac activity in rats during early postnatal ontogeny in vivo. Blockade of M 3 cholinergic receptors in 20-week-old animals increased heart rate and decreased blood pressure. In rats aging 8, 6, and 3 weeks, blockade of M 3 cholinergic receptors had little effect on R-R interval, but unexpectedly increased it in 1-week-old animals. It can be hypothesized that tonic inhibitory effect of the vagus nerve in adult rats is realized through M 3 cholinergic receptors of the heart. The decrease in heart rate during blockade of M 3 cholinergic receptors in 1-week-old rats was probably related to specific innervation of the heart in animals of this age.