Postsynaptic alpha 1-and alpha 2-adrenoceptor involvement in the vascular responses to neuronally released and exogenous noradrenaline in the hindlimb of the dog and cat.
The contribution of postsynaptic alpha 1-and alpha 2-adrenoceptors to vascular responses was investigated in the blood perfused hindlimbs of pentobarbitone-anaesthetised dogs and chloralose-anaesthetised cats. Responses were obtained to sympathetic nerve stimulation, noradrenaline, phenylephrine and UK-14,304. In the dog and cat hindlimbs, the response to phenylephrine was reduced by the selective alpha 1-adrenoceptor antagonist, prazosin, while that to UK-14,304, in the dog, was reduced by the alpha 2-adrenoceptor antagonist, rauwolscine. Responses to noradrenaline and sympathetic nerve stimulation were only partially blocked by prazosin in both the dog and cat, but were further reduced by the addition of rauwolscine. These results suggest that the hindlimb vasculature of the dog and cat responds to neuronally released, as well as exogenous, noradrenaline by activation of both postsynaptic alpha 1- and alpha 2-adrenoceptors.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002415:Cats; D004285:Dogs; D005260:Female; D006614:Hindlimb / Q000098:blood supply; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009474:Neurons / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism / Q000494:pharmacology* / Q000502:physiology; D010656:Phenylephrine / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D011941:Receptors, Adrenergic / Q000502:physiology*; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D012039:Regional Blood Flow / Q000187:drug effects; D013045:Species Specificity; D015016:Yohimbine / Q000494:pharmacology
D011941:Receptors, Adrenergic; D011942:Receptors, Adrenergic, alpha; D010656:Phenylephrine; D015016:Yohimbine; D009638:Norepinephrine; D011224:Prazosin