dihydroergotoxine and Hypotension

Topics: Adrenergic alpha-Antagonists; Aminophylline; Angina Pectoris; Bradycardia; Bronchial Diseases; Cerebrovascular Disorders; Coronary Circulation; Coronary Disease; Dementia; Dihydroergotoxine; Ethylamines; Furans; Humans; Hypotension; Injections, Intramuscular; Injections, Intravenous; Moxisylyte; Naphthalenes; Nitrates; Oxprenolol; Phenoxybenzamine; Practolol; Propionates; Propranolol; Vasodilator Agents

pO2 measurements in the cerebral cortex of cats have shown that the distribution of oxygen within the tissue becomes considerably affected by hypovolemic hypotension, in particular in the late period of oligemia. Pharmacological studies on this model show that the treatment of shock with a vasodilating drug such as papaverine leads to shunt-perfusion, thus impairing the oxygenation of brain tissue. In contrast, administration of the metabolically active drug dihydroergotoxine (DET, Hydergine) results in an improvement of the tissue pO2 distribution in the direction of a pre-shock state.

Topics: Animals; Blood Volume; Cats; Cerebrovascular Circulation; Dihydroergotoxine; Hypotension; Male; Oxygen; Papaverine

Phentolamine, dihydroergocristine and isoxsuprine were compared for their effects on the blood pressure in anaesthetized normotensive rats, in rats made hypotensive by ganglionic blockade or by pithing and in rats with noradrenaline-induced hypertension. Their ability to inhibit pressor responses elicited by electrical stimulation of the posterior hypothalamus and of the sympathetic outflow from the spinal cord was also investigated. All three drugs appeared very potent in inhibiting noradrenaline-induced hypertension and caused a dose-dependent fall in blood pressure in normotensive rats, which however was less pronounced with dihydroergocristine than with phentolamine and isoxsuprine. In hypotensive rats, dihydroergocristine caused a rise in blood pressure. At higher doses than those required to block noradrenaline-induced hypertension, the three drugs inhibited pressor responses elicited by electrical stimulation and were equally active on peripherally- and centrally-evoked responses. Simultaneous recording of heart rate and blood pressure, both in anaesthetized and in pithed rats, indicated a reflex origin for phentolamine-induced tachycardia and a direct cardiac stimulation for isoxsuprine. Reflex changes of heart rate were not observed with dihydroergocristine.

Topics: Animals; Blood Pressure; Dihydroergotoxine; Electric Stimulation; Ergoloid Mesylates; Heart Rate; Hypertension; Hypotension; Hypothalamus, Posterior; Isoxsuprine; Male; Norepinephrine; Pentolinium Tartrate; Phentolamine; Rats; Reflex; Spinal Nerves

Topics: Biomedical Research; Dihydroergotoxine; Drug Therapy; Ergoloid Mesylates; Ergot Alkaloids; Hypotension; Intraocular Pressure; Manometry; Ophthalmic Solutions; Rabbits; Research; Tonometry, Ocular

Topics: Blood Pressure; Blood Pressure Determination; Dihydroergotoxine; Dogs; Ergot Alkaloids; Ergotamine; Hypertension; Hypotension; Methylergonovine; Pharmacology; Research; Toxicology

Topics: Cardiovascular Agents; Dihydroergotoxine; Ergot Alkaloids; Hypotension; Hypotension, Orthostatic

Topics: Cardiovascular Agents; Dihydroergotoxine; Ergot Alkaloids; Hypotension; Oxytocics