Potentiation of Epinephrine Response in Vascular Tissue by Nicotine

  • A. Maiti


In studies of the influence of nicotine on the peripheral adrenergic neuroeffec tor transmission in the vascular smooth muscles, experiments were designed to analyse the vascular reactivity towards epinephrine following nicotine treatment. Topical or systemic administration of nicotine caused constriction of arterioles, metarterioles and precapillaries along with suppressed vasomotion in the peripheral microvasculature of rat mesocecum. Comparably, it also induced a transient strong contraction of isolated spirally cut cat aortic strip in vitro preparations. Such responses of nicotine were gradually decreased upon its repeated administration, but exhaustive washing and resting restored the reduced responses. While the tachyphylactic response of nicotine was pronounced, exposure of the above preparations to test doses of epinephrine not only restored the initial responses but the magnitude of such responses were greatly potentiated. On the other hand, nicotine produced tachyphylaxis depressed the responses to serotonin, histamine, amphetamine and tyrainine. It appeared that repeated nicotine pretreatment modulated the pattern of microcirculatory function and vascular smooth muscle responsiveness to epinephrine possibly through an alteration in the affinity constant for catecholamines at the terminal adrenoceptor of the effector cells


Vascular Smooth Muscle Sympathetic Activity Repeated Administration Vascular Reactivity Affinity Constant 
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Copyright information

© Springer-Verlag Berlin · Heidelberg 1972

Authors and Affiliations

  • A. Maiti
    • 1
  1. 1.Department of BiochemistryUniversity College of MedicineCalcuttaIndia

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