| pubmed-article:7813572 | pubmed:abstractText | The relative importance of extracellular Ca2+ influx and intracellular Ca2+ release for the vasoconstrictor response to Sgd 101/75 (4(2-imidazoline-amino)-2-methyl-indazol-chlorhydrate), an alpha 1-adrenoceptor agonist, was examined in perfused rabbit ear arteries. Sdg 101/75 induced a phasic and a tonic vasoconstrictor response in a concentration-dependent manner. It is a full agonist on the tonic response but a partial agonist on the phasic response. Nifedipine preferentially inhibited the tonic but not the phasic response to Sgd 101/75. Therefore, Sgd 101/75 appears to require both the intracellular Ca2+ release and extracellular Ca2+ influx for its phasic and tonic responses in rabbit ear arteries, respectively. | lld:pubmed |
