Effect of Muscarinic Cholinergic Receptor Blockade on Heart Activity in Rat Fetuses.

Cardiac activity parameters were analyzed in rat fetuses with preserved placental circulation on gestation days 17-20 after administration of muscarinic receptor blocker atropine either directly to the fetuses, or to the females. The obtained results attested to the absence of chronotropic effect from the cholinergic system in rats during the fetal period. At the same time, changes in heart rate variability observed after atropine injection showed that cholinergic receptors are involved into heart rhythm regulation in rat fetuses and that their role increases from the 17th to 20th day of the embryonic period.