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. 1978 Aug;63(4):683–687. doi: 10.1111/j.1476-5381.1978.tb17283.x

The effects of piperoxan on uptake of noradrenaline and overflow of transmitter in the isolated blood perfused spleen of the cat.

A G Blakeley, R J Summers
PMCID: PMC1668122  PMID: 28808

Abstract

1 The competitive alpha-adrenoceptor blocking agent, piperoxan, in concentrations up to 2 x 10(-4) M, produced large dose-dependent increases in transmitter overflow from the isolated blood perfused spleen of the cat following nerve stimulation at 10 hertz. 2 At concentrations greater than 2 x 10(-4) M, piperoxan produced a rise in perfusion pressure, a contraction of the splenic capsule, and a marked dose-dependent decrease in transmitter overflow. 3 Phenoxybenzamine (10(-4) M) and desmethylimipramine (3 x 10(-5) M) produced further increases in transmitter overflow when added after piperoxan. 4 Piperoxan (5.8 to 6.6 x 10(-6) M) had no effect on the recovery of 3H in the venous blood following the close arterial infusion or injection of (3H)-(--)-noradrenaline, indicating that the drug does not inhibit uptake of the amine. 5 Piperoxan produced dose-dependent inhibition of responses of the splenic vasculature to close arterial injection of 1 microgram of (--)-noradrenaline but was much less effective at inhibiting responses to nerve stimulation. At 2 x 10(-6) M piperoxan produced a considerable reduction of the response to injected noradrenaline but potentiated the response to nerve stimulation. 6 In isolated strips of cat splenic capsule, piperoxan produced a shift to the right of the dose-response curve to noradrenaline with no change of the maximum response. There was no evidence of a postsynaptic sensitizing effect of the type observed in the rat vas deferens.

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Selected References

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  1. Ariëns E. J. The structure-activity relationships of beta adrenergic drugs and beta adrenergic blocking drugs. Ann N Y Acad Sci. 1967 Feb 10;139(3):606–631. doi: 10.1111/j.1749-6632.1967.tb41232.x. [DOI] [PubMed] [Google Scholar]
  2. Bacq Z. M., Blakeley A. G., Summers R. J. The effects of amiodarone, an alpha and beta receptor antiagonist, on adrenergic transmission in the cat spleen. Biochem Pharmacol. 1976 May 15;25(10):1195–1199. doi: 10.1016/0006-2952(76)90368-3. [DOI] [PubMed] [Google Scholar]
  3. Blakeley A. G., Brown L., Dearnaley D. P., Woods R. I. Perfusion of the spleen with blood containing prostaglandin E1: transmitter liberation and uptake. Proc R Soc Lond B Biol Sci. 1969 Dec 23;174(1036):281–292. doi: 10.1098/rspb.1969.0094. [DOI] [PubMed] [Google Scholar]
  4. Blakeley A. G., Powis G., Summers R. J. An uptake mechanism for L-noradrenaline in the cat spleen, associated with the nerves but distinct from uptake. J Physiol. 1974 Apr;238(1):193–206. doi: 10.1113/jphysiol.1974.sp010518. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Blakeley A. G., Powis G., Summers R. J. The effects of pargyline on overflow of transmitter and uptake of noradrenaline in the cat spleen. Br J Pharmacol. 1973 Apr;47(4):719–728. doi: 10.1111/j.1476-5381.1973.tb08199.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Blakeley A. G., Summers R. J. The effects of labetalol (AH 5158) on adrenergic transmission in the cat spleen. Br J Pharmacol. 1977 Apr;59(4):643–650. doi: 10.1111/j.1476-5381.1977.tb07733.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Cambridge D., Davey M. J., Massingham R. Prazosin, a selective antagonist of post-synaptic alpha-adrenoceptors [proceedings]. Br J Pharmacol. 1977 Mar;59(3):514P–515P. [PMC free article] [PubMed] [Google Scholar]
  8. Drew G. M. Effects of alpha-adrenoceptor agonists and antagonists on pre- and postsynaptically located alpha-adrenoceptors. Eur J Pharmacol. 1976 Apr;36(2):313–320. doi: 10.1016/0014-2999(76)90084-4. [DOI] [PubMed] [Google Scholar]
  9. Drew G. M. Pharmacological characterisation of the presynaptic alpha-adrenoceptor in the rat vas deferens. Eur J Pharmacol. 1977 Mar 21;42(2):123–130. doi: 10.1016/0014-2999(77)90351-x. [DOI] [PubMed] [Google Scholar]
  10. Dubocovich M. L., Langer S. Z. Negative feed-back regulation of noradrenaline release by nerve stimulation in the perfused cat's spleen: differences in potency of phenoxybenzamine in blocking the pre- and post-synaptic adrenergic receptors. J Physiol. 1974 Mar;237(3):505–519. doi: 10.1113/jphysiol.1974.sp010495. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Endo T., Starke K., Bangerter A., Taube H. D. Presynaptic receptor systems on the noradrenergic neurones of the rabbit pulmonary artery. Naunyn Schmiedebergs Arch Pharmacol. 1977 Feb;296(3):229–247. doi: 10.1007/BF00498689. [DOI] [PubMed] [Google Scholar]
  12. Häggendal J., Johansson B., Jonason J., Ljung B. Effects of phenoxybenzamine on transmitter release and effector response in the isolated portal vein. J Pharm Pharmacol. 1972 Feb;24(2):161–164. doi: 10.1111/j.2042-7158.1972.tb08954.x. [DOI] [PubMed] [Google Scholar]
  13. Jurkiewicz A., Jurkiewicz N. H. Dual effect of alpha-adrenoceptor antagonists in rat isolated vas deferens. Br J Pharmacol. 1976 Feb;56(2):169–178. doi: 10.1111/j.1476-5381.1976.tb07439.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. OHLIN P., STROMBLAD B. C. Observations on the isolated vas deferens. Br J Pharmacol Chemother. 1963 Apr;20:299–306. doi: 10.1111/j.1476-5381.1963.tb01469.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Starke K., Borowski E., Endo T. Preferential blockade of presynaptic alpha-adrenoceptors by yohimbine. Eur J Pharmacol. 1975 Dec;34(2):385–388. doi: 10.1016/0014-2999(75)90268-x. [DOI] [PubMed] [Google Scholar]
  16. Swedin G. Postnatal development of the mechanical response of the isolated rat vas deferens to nerve stimulation. Acta Physiol Scand. 1972 Feb;84(2):217–223. doi: 10.1111/j.1748-1716.1972.tb05172.x. [DOI] [PubMed] [Google Scholar]

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