RELATIONSHIP BETWEEN THE NERVE ACTION-POTENTIAL AND TRANSMITTER RELEASE FROM SYMPATHETIC POSTGANGLIONIC NERVE-TERMINALS

At the skeletal neuromuscular junction, electrophysiological methods have provided much useful information about the mechanisms involved in the release of transmitter1-3. At the autonomic neuroeffector junction it has not been possible to carry out similar studies4. Here we report a method of extracellular recording which allows simultaneous measurement of both the nerve action potential and transmitter release from postganglionic sympathetic nerve terminals. We have confirmed that release is intermittent5,6, but the importance of this new approach is that the relationship between the nerve terminal action potential and transmitter release can be studied unambiguously for the first time. Thus we are able to show unequivocally that intermittence is caused by a low probability of release in the invaded varicosity and not by failure of the action potential to invade the varicosity. © 1987 Nature Publishing Group.