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Inhibitory effects of procaine on contraction and calcium movement in vascular and intestinal smooth muscles
Author(s) -
Ahn H.Y.,
Karaki H.
Publication year - 1988
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1988.tb11590.x
Subject(s) - procaine , contraction (grammar) , taenia coli , carbachol , vascular smooth muscle , chemistry , muscle contraction , aorta , endocrinology , caffeine , medicine , anatomy , calcium , pharmacology , anesthesia , smooth muscle , stimulation
1 The effects of procaine on muscle tension and 45 Ca 2+ movements were investigated in vascular smooth muscle of the rabbit aorta and intestinal smooth muscle of the taenia isolated from guinea‐pig caecum. 2 Procaine (10 m m ) induced a contraction in the taenia but had little effect on the resting tension in the aorta. 3 Procaine, 0.5–10 mM, relaxed the sustained contractions induced by 65.4 mM KCl and 10 −6 m noradrenaline in the aorta, and by 45.4 mM KCl, 10 −6 m carbachol and 10 −6 m histamine in the taenia. The inhibitory effect of procaine on the high K + ‐induced contractions was antagonized by external Ca 2+ but not by the Ca 2+ channel activators, Bay K 8644 and CGP 28,392. 4 45 Ca 2+ uptake was increased by high K + or noradrenaline in the aorta and by high K + or carbachol in the taenia. The increments were inhibited by procaine at the concentrations needed to inhibit the muscle contractions. 5 In a Ca 2+ ‐free solution, noradrenaline and caffeine induced a transient contraction in the aorta, whereas a second application of each stimulant was almost ineffective. Addition of 1–10 mM procaine shortly before the first application of the stimulant inhibited the contraction. After washing the muscle with a Ca 2+ ‐free solution without procaine, the second application of the stimulant induced a greater contraction than that in control muscle without procaine pretreatment. 6 Noradrenaline and caffeine released 45 Ca 2+ from a cellular site in the aorta. Procaine inhibited the effects of these stimulants. 7 It was concluded that procaine may inhibit both the opening of Ca 2+ channels and the release of Ca 2+ from cellular stores and the former but not the latter effect may be attributable to a local anaesthetic action.