Cardiovascular reactivity of neonatal and adult sheep to autonomic stimuli during adrenergic depletion.
The cardiovascular responses of the neonatal and adult sheep to autonomic agonists and antagonists were studied in the resting state and following adrenergic neuronal depletion with reserpine. Both the neonates and adults showed similar supersensitivity of the effector system of the peripheral circulation to alpha adrenergic stimulation with catecholamines. In addition, the neonates exhibited supersensitivity of the myocardial effector system to beta-adrenergic stimulation. Unusual finding was a marked supersensitivity of the heart and peripheral circulation to cholinergic receptor blockade with atropine, the mechanisms of which are as yet unclear.
D000109:Acetylcholine / Q000494:pharmacology; D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D001285:Atropine / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D002320:Cardiovascular Physiological Phenomena; D002319:Cardiovascular System / Q000187:drug effects; D002395:Catecholamines / Q000494:pharmacology; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D007545:Isoproterenol / Q000494:pharmacology; D010277:Parasympathomimetics; D010643:Phenoxybenzamine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011941:Receptors, Adrenergic / Q000187:drug effects*; D011950:Receptors, Cholinergic / Q000187:drug effects*; D012110:Reserpine / Q000494:pharmacology*; D012756:Sheep / Q000502:physiology*; D014439:Tyramine / Q000494:pharmacology
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D002395:Catecholamines; D010277:Parasympathomimetics; D011941:Receptors, Adrenergic; D011950:Receptors, Cholinergic; D010643:Phenoxybenzamine; D001285:Atropine; D012110:Reserpine; D011433:Propranolol; D007545:Isoproterenol; D000109:Acetylcholine; D014439:Tyramine