Effect of dopexamine hydrochloride on contractions of rabbit isolated aorta evoked by various agonists.

  title={Effect of dopexamine hydrochloride on contractions of rabbit isolated aorta evoked by various agonists.},
  author={O. Nedergaard},
  journal={Pharmacology \& toxicology},
  volume={74 1},
  • O. Nedergaard
  • Published 1994
  • Chemistry, Medicine
  • Pharmacology & toxicology
The inhibitory affinity of dopexamine hydrochloride to postsynaptic adrenoceptors, cholinoceptors, 5-hydroxytryptamine and histamine receptors was studied in rabbit isolated aorta. Dopexamine (10(-7)-10(-5) M) antagonized competitively the contractions of rabbit aorta evoked by noradrenaline (pA2: 6.60). Neither cocaine plus corticosterone nor cocaine, corticosterone plus propranolol altered the inhibition (pA2: 6.77 and 6.63, respectively). The antagonism of dopexamine against noradrenaline… Expand
Effect of dopexamine hydrochloride on sympathetic neuroeffector transmission in rabbit isolated pulmonary artery.
It is concluded that the dopexamine-induced enhancement of neurogenic contractions is not due to either inhibition of neuronal and extraneuronal uptake of noradrenaline or an agonist action on prejunctional beta 2-adrenoceptors, and that the dopamine-induced increase in resting tension is due to its metabolite methyldopexamine. Expand
Characterization of the mechanism involved in the relaxant response of dopexamine in the guinea pig pulmonary artery in vitro.
Dopexamine-induced relaxation in PA seems to involve the release of peptides such as VIP and CGRP, an effect mediated by a cyclic adenosine monophosphate (cAMP)-dependent mechanism. Expand
Different effects of dopamine and dopexamine on the isolated perfused rat kidney.
The data suggest that the diuretic and natriuretic effects of dopexamine in humans may not result from a direct action on the kidney. Expand
Immune, microvascular and haemodynamic effects of dopexamine in rodent models of laparotomy & endotoxaemia
The series of investigations that make up this thesis set out to explore the nature of any such dose-related effects and reveal potent anti-inflammatory effects of dopexamine in the absence of haemodynamic effects. Expand


Inhibition of Uptake1 by dopexamine hydrochloride in vitro)
The cardiac stimulant effect of dopexamine hydrochloride reported in dogs and in patients with heart failure, may therefore be due in part to potentiation of endogenous catecholamines. Expand
Receptors for 5-hydroxytryptamine in rabbit blood vessels: activation of alpha adrenoceptors in rabbit thoracic aorta.
The contractile response to concentrations of 5-HT below 1 X 10(-5) M is mediated exclusively by serotonergic receptors, and results were obtained in aortic rings from reserpine-pretreated rabbits. Expand
The effects of dopexamine on the cardiovascular system of the dog
Dopexamine produces a different cardiovascular profile from dopamine in the anaesthetized and conscious dog, but in contrast to dopamine, dopexamine reduces afterload and produces only mild inotropic stimulation. Expand
Endothelium modulates the effects of α-adrenoceptor agonists in vascular smooth muscle
Abstract 1. 1. The contraction induced by clonidine and guanfacine but not phenylephrine was enhanced in endothelium-denuded and methylene blue pretreated rabbit aortic, pulmonary artery rings andExpand
Effect of histamine on aorta preparations of different species.
The effect of histamine on aorta preparations of 5 different species was studied and all the contraction effects proved to be H1-mediated as they were antagonized by mepyramine. Expand
Dopexamine: a novel agonist at peripheral dopamine receptors and β2‐adrenoceptors
The combination of agonist properties at peripheral dopamine receptors and at β2‐adrenoceptors, with little or no activity at α‐ and β1‐adreneceptors gives dopexamine a novel pharmacological profile, which may confer advantages over dopamine in the treatment of acute heart failure. Expand
Mechanisms mediating the positive inotropic and chronotropic changes induced by dopexamine in the anesthetized dog.
The positive inotropic and chronotropic effects of DPX in the intact dog are due primarily to baroreceptor-mediated stimulation and inhibition of neuronal uptake of norepinephrine. Expand
Role of cyclic GMP in the modulation by endothelium of the adrenolytic action of prazosin in the rat isolated aorta
It was concluded that the change in the mode of antagonism of prazosin after endothelium removal could be related to an alteration in the efficacy of the agonist, brought about by achange in the tissue levels of cyclic GMP. Expand
Effect of chlorpromazine on sympathetic neuroeffector transmission in the rabbit isolated pulmonary artery and aorta
It is concluded that chlorpromazine and prazosin are potent inhibitors of postsynaptic α1‐ adrenoceptors and are also inhibitors of Uptake. Expand
Prejunctional effects of 5-hydroxytryptamine on noradrenergic nerves in the cardiovascular system.
The evidence for the existence of these two types of prejunctional 5-HT receptor is discussed together with findings to date on their distribution and possible functional importance in the whole animal. Expand