Abstract
Pharmacologic and electron microscopic cytochemical procedures were performed in the rat vas deferens in order to study the localization of exogenously administered 5-hydroxytryptamine (5-HT) in adrenergic nerve endings. Exogenous 5-HT accumulated in the nerve terminals was not incorporated into the intravesicular compartment, demonstrating that it is unable to displace norepinephrine from this storage site. Administration of α-methyl-m-tyrosine markedly reduced the norepinephnine content of the vas deferens as well as the dense cores of the granulated vesicles of nerve endings. The administration of 5-HT to α-methyl-m-tyrosine-pretreated rats resulted in a marked increase of 5-HT concentration in the organ and in the reappearance of the dense cores of both types of vesicles observed within the endings. That these cores corresponded to 5-HT was confirmed by the results of cytochemical tests. These data siggest that, under appropriate conditions, 5-HT can be incorporated and stored in the intravesicular compartment of the postganglionic sympathetic nerve endings normally storing norepmepllnine.
Footnotes
- Received July 22, 1968.
- Accepted October 31, 1968.
- © 1969 by The Williams & Wilkins Co.
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