CHANGES IN NORADRENALINE RELEASE RATE AND NORADRENALINE STORAGE VESICLES DURING PROLONGED ACTIVITY OF SYMPATHETIC NEURONES

Prolonged cold exposure produces fluctuations in noradrenaline (NA) release rate. The nerve terminals in the rat heart show changes which parallel the changes in release rate. There is an initial rise in vesicular NA uptake and storage capacity, which coincides with the peak release rate. This is followed by a fall in both NA content and storage capacity of the vesicles; this corresponds to a steeply declining release rate.