General paper
Prejunctional α1-adrenoceptors modify release of [3H]noradrenaline in the guinea-pig vas deferens

https://doi.org/10.1016/0306-3623(90)90595-DGet rights and content

Abstract

  • 1.

    1. Several α1- and α2-adrenoceptor agonists and antagonists were examined for effects on spontaneous and stimulus-evoked release of [3H]noradrenaline from sympathetic nerves in guinea-pig vas deferens.

  • 2.

    2. Prazosin (0.1 and 1 μM), phentolamine (30 μM) and yohimbine (10 μM) each enhanced the stimulus-evoked release of [3H]noradrenaline.

  • 3.

    3. Prazosin and phentolamine increased the spontaneous outflow of [3H]noradrenaline, whereas yohimbine was without effect.

  • 4.

    4. Methoxamine (10 μM) and clonidine (0.1 μM) inhibited the stimulus-evoked release of [3H]noradrenaline, whereas only methoxamine (1 μM) decreased the spontaneous outflow of [3H]noradrenaline.

  • 5.

    5. The identity of prejunctional α-adrenoceptors in the guinea-pig vas deferens is discussed.

References (47)

  • M.J. Anderson et al.

    The effect of high dose of prazosin and transmural stimulation, on the disposition of transmitter noradrenaline in the rabbit pulmonary artery and the dog saphenous vein

    Br. J. Pharmac.

    (1979)
  • E.O. Bamidele

    Prazosin and asthma in Lagos

    Current Ther. Res.

    (1986)
  • D.T. Beattie et al.

    Effects of calcium channel antagonists on action potential conduction and transmitter release in the guinea-pig vas deferens

    Br. J. Pharmac.

    (1986)
  • L. Bradley et al.

    Effects of prazosin, phentolamine and yohimbine on noradrenergic transmission in the rat right ventricle in vitro

    J. Auton. Pharmac.

    (1983)
  • D. Cambridge et al.

    Prazosin, a selective antagonist of post-synaptic α-adrenoceptors

    Br. J. Pharmac.

    (1977)
  • I. Cavero et al.

    Effects of clonidine, prazosin and phentolamine on heart rate and coronary sinus catecholamine concentration during cardioaccelerator nerve stimulation in spinal dogs

    Br. J. Pharmac.

    (1979)
  • L. Cubeddu et al.

    Release of norepinephrine and dopamine-β-hydroxylase by nerve stimulation. V. Enhanced release associated with a granular effect of a benzoquinolizine derivative with reserpine-like properties

    J. Pharmac. Exp. Ther.

    (1975)
  • A. de Jonge et al.

    A lipophilic selective α1-adrenoceptor agonist α2-(2-chloro-5-trifluoromethylphenylimine) imidazoline (St 587)

    Life Sci.

    (1981)
  • A. de Jonge et al.

    Inhibitory effect of alpha-1 adrenoceptor stimulation on cardiac sympathetic neurotransmission in pithed normotensive rats

    J. Pharmac. Exp. Ther.

    (1986)
  • J.R. Docherty

    An investigation of presynaptic α1-adrenoceptor subtypes in the pithed rat heart and in the rat isolated vas deferens

    Br. J. Pharmac.

    (1984)
  • M.L. Dubocovich et al.

    Lack of correlation between presynaptic inhibition of noradrenaline release and end organ responses during nerve stimulation

    Br. J. Pharmac.

    (1980)
  • P.E. Hicks et al.

    Possible involvement of presynaptic α1-adrenoceptors in the effects of idazoxan and prazosin on 3H-noradrenaline release from tail arteries of SHR

    Naunyn-Schmiedeb. Arch. Pharmac.

    (1986)
  • J. Kapocsi et al.

    Neurochemical evidence for two types of presynaptic alpha2-adrenoceptors

    Neurochem. Res.

    (1987)
  • Cited by (11)

    • Low temperature prevents potentiation of norepinephrine release by phenylephrine

      2001, Neurochemistry International
      Citation Excerpt :

      A selective α1-adrenoceptor agonist l-phenylephrine (l-PE) has been widely used as a directly acting sympathomimetic amine (Vizi et al., 1985). It is accepted that l-PE acts directly on effector sympathetic cells, while it can indirectly influence them by increasing the release of norepinephrine (NE) from storage vesicules via α1-adrenoceptors (Ellis et al., 1990). It is generally accepted that activation can induce the release of neurotransmitter in two different ways.

    View all citing articles on Scopus

    Present address: Bulgarian Academy of Science, Institute of Physiology, Acad. G. Bonchev str. bl. 23, 1113 Sofia, Bulgaria.

    Present address: Institute of Pharmacology, Bulgarian Medical Academy, 1431 Sofia, Bulgaria.

    View full text