Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1988-2-2
pubmed:abstractText
Excitatory junction potentials (e.j.p.s) evoked by nerve stimulation with 15 pulses at 1 Hz were recorded from muscle cells of the rabbit isolated mesenteric artery. Clonidine and B-HT 933 depressed all e.j.p.s in the train. The percentage inhibition was inversely related to the number of pulses. Yohimbine, rauwolscine and tolazoline reduced the early e.j.p. amplitudes but enhanced the later ones. The percentage facilitation of e.j.p.s increased with the number of pulses until a maximum was reached. Prazosin and corynanthine did not influence the first few e.j.p.s but potentiated the subsequent ones; their effects were less pronounced than those of yohimbine and rauwolscine. All the drugs antagonized the inhibition by clonidine but the effects of yohimbine and rauwolscine were more marked than those of prazosin and corynanthine. Phenylephrine, St 587 and noradrenaline depressed the e.j.p.s. Yohimbine diminished the effects of these substances and was a stronger antagonist of phenylephrine than prazosin. We suggest that, in the rabbit mesenteric artery, noradrenaline and the neuroeffector transmitter (probably ATP) are co-released from the terminals of postganglionic sympathetic nerves. Noradrenaline activates presynaptic alpha 2-adrenoceptors and thereby depresses transmitter release. The degree of presynaptic inhibition depends on the number of pulses applied, i.e. on the biophase concentration of noradrenaline.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0014-2999
pubmed:author
pubmed:issnType
Print
pubmed:day
10
pubmed:volume
143
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
151-61
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1987
pubmed:articleTitle
Electrophysiological evidence for an alpha 2-adrenergic inhibitory control of transmitter release in the rabbit mesenteric artery.
pubmed:affiliation
Department of Pharmacology, University of Freiburg, F.R.G.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't