Comparison of Spontaneous Loss of Catecholamines and Atp in Vitro From Isolated Bovine Adrenomedullary, Vesicular Gland, Vas Deferens and Splenic Nerve Granules

SUMMARY The molar ratio catecholamines/ATP in the high speed sediment from homogenates of bovine adrenal medulla, vesicular gland, vas deferens and splenic nerve was relatively close to the‘equivalence ratio’of 4/1. On incubation in vitro the loss of amines and ATP from the medullary granules was slow and largely parallel. Thus the original amine/ATP ratio was maintained. The amine loss from the nerve granules occurred at a very high, and from the vesicular gland and vas deferens granules at an intermediate, rate. On the other hand, the decrease in ATP in these preparations was quite slow, leading to a marked change in the original amine/ATP ratio. These findings are regarded as further evidence of functional differences between granules derived from chromaffin cells and from sympathetic nerve tissue, and even between nerve granules from‘long’and 'short’noradrenergic neurons. The possible implications of these in vitro differences in amine and ATP release are discussed in relation to the mechanisms of amine release in vivo .