ISSN:
1438-8359
Keywords:
Phenol
;
Preservative for injections
;
Intracellular calcium stores
;
Vascular smooth muscle
;
Resistance artery
;
Protamine
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Although phenol has long been used clinically as a neurolytic agent or as a preservative for injections, little information is available regarding its direct vascular action. We therefore studied the effects of phenol (0.1 μM–2mM) on isolated rabbit small mesenteric arteries, using isometric tension recording methods. All experiments were performed on endothelium-denuded strips. Phenol (≥10 μM) generated transsient contractions in a concentration-dependent manner in both normal Krebs and Ca2+-free solutions with EC50 values (concentrations that produced 50% of the maximal response) of 39.8 μM and 99.7 μM, respectively. Depletion of intracellular Ca2+ stores by A23187 or ryanodine completely elimited the phenol-induced contractions. When caffeine (10 mM) and noradrenaline (NA, 10μM) were consecutively applied in Ca2+-free solution with an interval of 7 min (sufficient to prevent caffeine-induced inhibition of Ca2+ sensitivity), caffeine eliminated the contractions induced by subsequent application of NA. In similar experiments where phenol (1 mM) and NA (10 μM) were consecutively applied in Ca2+-free solution, phenol significantly inhibited contractions induced by subsequent application of NA. Phenol (0.1 mM, ∼EC65), applied in the presence of either 128 mM K+ or NA (10 μM), produced transient vasoconstrictions superimposed on both high K+-and NA-induced contractions, but had a lesser effect on maintenance of these contractions. The vascular responses to high K+, NA, and caffeine after washout of phenol were not significantly different from those before application of phenol (up to 2 mM). The results suggest that phenol stimulates Ca2+ release from intracellular Ca2+ stores, which are sensitive to both caffine and NA in this resistance artery. The effect does not appear to reflect a toxic effect on vascular smooth muscle. It seems unlikely that phenol causes adverse hemodynamic changes because of the observed direct vascular action.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02482064
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