EFFECT OF PYRIDINE AND ITS METHYLATED DERIVATIVES ON STORAGE BY RAT PINEAL NERVES OF MONOAMINERGIC NEUROTRANSMITTER

In previous work of our laboratory, it was demonstrated that collidine (2-4-6-trimethylpyridine) applied briefly to fresh tissues extracted noradrenaline or closely related compound/s of neuronal origin. This e ffect gave rise to the abolition of osmiophilia and chromaffin reactio n of electron-dense cores of monoaminergic synaptic vesicles and to th e extraction of radioactive compounds in tissues that had previously t aken up tritiated noradrenaline. In this work, the role of the pyridin e ring and its progressive methylation on the monoamine releasing effe ct was investigated. For this purpose, the effect of pyridine, two pic olines (2 and 4 monomethylpyridines) and a lutidine (2-6-dimethylpyrid ine) was compared to the effect of collidine. It was found that pyridi ne has a much smaller effect than collidine on the histochemical react ivity of monoaminergic synaptic vesicles and on the extraction of trit iated compounds and that its extent was dependent upon the number of m ethyl groups incorporated in the pyridine ring.