These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Mechanisms of the release of 3H-noradrenaline by dimethylphenylpiperazinium (DMPP) in the rat vas deferens.
    Author: Niebler M, Trendelenburg U.
    Journal: Naunyn Schmiedebergs Arch Pharmacol; 1990; 341(1-2):43-9. PubMed ID: 2314482.
    Abstract:
    In the rat vas deferens, DMPP is a substrate of uptake1 (Km = 11.5 mumol/l). After block of vesicular uptake, monoamine oxidase and catechol-O-methyl transferase, after loading of the tissue with 3H-noradrenaline, and in calcium-free solution (i.e., when axoplasmic 3H-noradrenaline levels were high and when depolarization-induced exocytotic release was impossible), DMPP induced a pronounced outward transport of 3H-noradrenaline. On the other hand, when, in similar experiments, vesicular uptake and monoamine oxidase were intact (i.e., when axoplasmic 3H-noradrenaline levels were low), DMPP induced very little outward transport of 3H-noradrenaline. This discrepancy indicates that DMPP has little ability to mobilize vesicularly stored 3H-amine. When the medium contained calcium (catechol-O-methyl transferase inhibited, all other mechanisms intact), 100 (but not 10) mumol/l DMPP induced a hexamethonium-sensitive release of 3H-noradrenaline of short duration. Hence, in the presence of extracellular calcium, 100 mumol/l DMPP elicits exocytotic release via activation of hexamethonium-sensitive nicotinic acetylcholine receptors. DMPP inhibits the monoamine oxidase of rat heart homogenate with an IC50 of about 100 mumol/l.
    [Abstract] [Full Text] [Related] [New Search]