Norepinephrine(NE)endogenously released following electrical field stimulation(prazosin and TTX sensitive responses),produced a biphasic contraction of the rat vas deferens(RVD).The initial transient contraction was d...Norepinephrine(NE)endogenously released following electrical field stimulation(prazosin and TTX sensitive responses),produced a biphasic contraction of the rat vas deferens(RVD).The initial transient contraction was decreased by 30μmol/L ryanodine andμmol/L nifedipine while the secondary component was abolished by 2μmol/L nifedipine but increased by 30μmol/L ryanodine.Exogenously added NE produced biphasic contractions of the RVD.These contractions were inhibited by 2μmol/L nifedipine.Ryanodine(30μmol/L)decreased both phases by about 50%.We conclude that ryanodine binding sites reside in RVD endoplasmic reticulum(ER).There was a lack of uniformity in the effect of ryanodine against different phases of alpha-adrenergic stimulation may be indicative of two modes of stimulation-contraction coupling process related to this stimulation.展开更多
基金This work was supported bv a granl-in-aid awarded by the Medical Re-search Council of Canadaa Career Investigator Awand(CY Kwan)from the Heart and Stroke Foun-dation of Ontario.
文摘Norepinephrine(NE)endogenously released following electrical field stimulation(prazosin and TTX sensitive responses),produced a biphasic contraction of the rat vas deferens(RVD).The initial transient contraction was decreased by 30μmol/L ryanodine andμmol/L nifedipine while the secondary component was abolished by 2μmol/L nifedipine but increased by 30μmol/L ryanodine.Exogenously added NE produced biphasic contractions of the RVD.These contractions were inhibited by 2μmol/L nifedipine.Ryanodine(30μmol/L)decreased both phases by about 50%.We conclude that ryanodine binding sites reside in RVD endoplasmic reticulum(ER).There was a lack of uniformity in the effect of ryanodine against different phases of alpha-adrenergic stimulation may be indicative of two modes of stimulation-contraction coupling process related to this stimulation.
