Functional characterisation of α1-adrenoceptors in denervated rat vas deferens

  • Marcelo Campos
  • Paola de Lucena Morais
  • André S. Pupo
Original Article
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Abstract

We investigated whether or not surgical denervation of the rat vas deferens changes the α1-adrenoceptor subtypes involved in the contractions to noradrenaline. Denervated vas deferens was ≈22 times more sensitive to noradrenaline (pD2=7.35±0.04) than control vas (pD2=6.01±0.03). This difference in noradrenaline potency was eliminated when cocaine (6 μM) was added to control vas (pD2=7.22±0.04). The noradrenaline-induced contractions of control and denervated vas deferens were insensitive to the α1B/α1D-adrenoceptor alkylating agent chloroethylclonidine (100 μM, 45 min). The concentration-response curves to noradrenaline in control and denervated vas deferens were competitively antagonised by prazosin (pA2≈9.6), WB-4101 (pA2≈9.5), 5-methyl urapidil (pA2≈8.4), phentolamine (pA2≈8.7), yohimbine (pA2≈6.9), BMY 7378 (pA2≈6.9) and indoramin (pA2≈8.7). After the treatment of control and denervated vas deferens with phenoxybenzamine, the partial agonist oxymetazoline antagonised competitively the concentration-response curves to noradrenaline showing pA2 values ≈7.4 in both groups. We conclude that noradrenaline-induced contractions in control and denervated rat vas deferens are mediated by α1A-adrenoceptors and that surgical denervation of the rat vas deferens is not able to change the α1-adrenoceptor subtypes involved in the contractions to noradrenaline.

Keywords

Rat vas deferens Denervation α1A-Adrenoceptors 
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Notes

Acknowledgements

This work was supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP – Proc. No. 98/11031-2 to A.S. Pupo). M. Campos and P.L. Morais received studentships from FAPESP and CAPES, respectively.

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Copyright information

© Springer-Verlag 2003

Authors and Affiliations

  • Marcelo Campos
    • 1
  • Paola de Lucena Morais
    • 1
  • André S. Pupo
    • 1
  1. 1.Department of Pharmacology, Instituto de BiociênciasUNESPBotucatuBrazil

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