Development of cholinergic neuroeffector transmission in the avian heart. Implications for regulatory mechanisms

A brief outline of the ontogenesis of cholinergic neuroeffector transmission in the embryonic chick heart is given. It is important to define the development of neuroeffector transmission to evaluate the possible effects on postjunctional membrane properties. The membrane response of the aneural chick heart undergoes a qualitative change to muscarinic agonist at a time well before cholinergic innervation. This suppressed response can be revealed later in life, even in adults, when provision is made to exclude Gi/Go and or K channel activity.