Effect of hydroxydopamine on the small dense-cored vesicles in the cholinergic nerve terminals of the rat bladder
Hoyes, A.D.; Barber, P.
Journal of Anatomy 127(Pt 3): 533-542
1978
ISSN/ISBN: 0021-8782 PMID: 744748 Document Number: 124421
A simple quantitative technique based on estimation of the proportion of terminal profiles observed in thin sections which contained the vesicles was employed to assess the effect of hydroxydopamine on the small dense-cored vesicles in the cholinergic axonal terminals in the rat bladder. In animals perfused with fixative at different intervals after injection of 100 mg/kg 6-hydroxydopamine there was a considerable, but short-lived, increase in the proportion of terminal profiles containing the vesicles. In animals perfused 1 h after injection of different doses of 6-hydroxydopamine there was an increase in the proportion of vesicle-containing terminal profiles only at dose levels of 25 mg/kg and above. Incubation of specimens of bladder in buffer containing 1 mg/ml 6- or 5-hydroxydopamine was also accompanied by a considerable increase in the proportion of vesicle-containing profiles over that observed in incubated and unincubated controls. In contrast to the situation in untreated animals, after pre-treatment with reserpine there was little difference between the proportion of terminal profiles containing the vesicles in specimens fixed immediately after removal and the proportion observed in perfusion-fixed specimens from both control and reserpine-treated animals. There was no alteration in the response to incubation in 5-hydroxydopamine, and only a limited reduction in the response to incubation in 6-hydroxydopamine. From estimates of the proportion of small vesicles in the terminals with dense cores, it was calculated that, even when they were present in 50% of the terminal profiles, they accounted for only 1.14% of all the small vesicles in the terminals.