Studies on the autonomic nervous system with SK&F 92657, a new antihypertensive agent causing direct arterial vasodilatation and beta-adrenoceptor blockade. 1981

E M Taylor, and R J Eden, and R Fielden, and D A Owen

The beta-adrenoceptor-blocking properties of SK&F 92657, D,L-3-[2-(3-t-butylamino-2-hydroxypropoxy)phenyl]-6-hydrazinopyridazine, were studied in both in vivo and in vitro. The pA2 against isoprenaline tachycardia (beta 1 effect) in isolated guinea pig right atria was 7.16 (6.14-7.87). In contrast, histamine-induced tachycardia was unaffected by SK&F 92657. The pA2 against isoprenaline relaxation of guinea pig tracheal muscle (beta 2 effect) was 7.03 (6.28-7.61). In vivo ED50's against isoprenaline tachycardia (beta 1) and vasodilation (beta 2) in anesthetized cats were 5.7 x 10(-8) and 6.2 x 10(-8) mol/kg, i.v., respectively. Increases in heart rate caused either by activation of autonomic reflexes or by stimulation of efferent cardiac sympathetic nerves were also antagonized by SK&F 92657. The beta-adrenoceptor blockade caused by SK&F 92657 was shown to be competitive both in vivo an vitro and to be equally effective on beta 1- and beta 2-receptor populations. SK&F 92657 was a weak partial agonist in vivo and had only minimal local anesthetic activity. The compound had no direct effect on the functioning of the autonomic nervous system, apart from beta-blockade, but reflexes maintaining homeostasis were reduced because (1) SK&F 92657 is a beta-adrenoceptor antagonist preventing reflex increases in heart rate and cardiac output, and (2) it is a potent vasodilator counteracting reflex vasoconstriction. Postural reflexes were unaffected because SK&F 92657 selectively dilates arterial blood vessels.

UI MeSH Term Description Entries
D011187 Posture The position or physical attitude of the body. Postures
D011724 Pyridazines Six-membered rings with two adjacent nitrogen atoms also called 1,2-diazine.
D011943 Receptors, Adrenergic, beta One of two major pharmacologically defined classes of adrenergic receptors. The beta adrenergic receptors play an important role in regulating CARDIAC MUSCLE contraction, SMOOTH MUSCLE relaxation, and GLYCOGENOLYSIS. Adrenergic beta-Receptor,Adrenergic beta-Receptors,Receptors, beta-Adrenergic,beta Adrenergic Receptor,beta-Adrenergic Receptor,beta-Adrenergic Receptors,Receptor, Adrenergic, beta,Adrenergic Receptor, beta,Adrenergic beta Receptor,Adrenergic beta Receptors,Receptor, beta Adrenergic,Receptor, beta-Adrenergic,Receptors, beta Adrenergic,beta Adrenergic Receptors,beta-Receptor, Adrenergic,beta-Receptors, Adrenergic
D001794 Blood Pressure PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS. Systolic Pressure,Diastolic Pressure,Pulse Pressure,Pressure, Blood,Pressure, Diastolic,Pressure, Pulse,Pressure, Systolic,Pressures, Systolic
D002346 Carotid Sinus The dilated portion of the common carotid artery at its bifurcation into external and internal carotids. It contains baroreceptors which, when stimulated, cause slowing of the heart, vasodilatation, and a fall in blood pressure. Sinus, Carotid
D002415 Cats The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801) Felis catus,Felis domesticus,Domestic Cats,Felis domestica,Felis sylvestris catus,Cat,Cat, Domestic,Cats, Domestic,Domestic Cat
D004305 Dose-Response Relationship, Drug The relationship between the dose of an administered drug and the response of the organism to the drug. Dose Response Relationship, Drug,Dose-Response Relationships, Drug,Drug Dose-Response Relationship,Drug Dose-Response Relationships,Relationship, Drug Dose-Response,Relationships, Drug Dose-Response
D006168 Guinea Pigs A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research. Cavia,Cavia porcellus,Guinea Pig,Pig, Guinea,Pigs, Guinea
D000319 Adrenergic beta-Antagonists Drugs that bind to but do not activate beta-adrenergic receptors thereby blocking the actions of beta-adrenergic agonists. Adrenergic beta-antagonists are used for treatment of hypertension, cardiac arrhythmias, angina pectoris, glaucoma, migraine headaches, and anxiety. Adrenergic beta-Antagonist,Adrenergic beta-Receptor Blockader,Adrenergic beta-Receptor Blockaders,beta-Adrenergic Antagonist,beta-Adrenergic Blocker,beta-Adrenergic Blocking Agent,beta-Adrenergic Blocking Agents,beta-Adrenergic Receptor Blockader,beta-Adrenergic Receptor Blockaders,beta-Adrenoceptor Antagonist,beta-Blockers, Adrenergic,beta-Adrenergic Antagonists,beta-Adrenergic Blockers,beta-Adrenoceptor Antagonists,Adrenergic beta Antagonist,Adrenergic beta Antagonists,Adrenergic beta Receptor Blockader,Adrenergic beta Receptor Blockaders,Adrenergic beta-Blockers,Agent, beta-Adrenergic Blocking,Agents, beta-Adrenergic Blocking,Antagonist, beta-Adrenergic,Antagonist, beta-Adrenoceptor,Antagonists, beta-Adrenergic,Antagonists, beta-Adrenoceptor,Blockader, Adrenergic beta-Receptor,Blockader, beta-Adrenergic Receptor,Blockaders, Adrenergic beta-Receptor,Blockaders, beta-Adrenergic Receptor,Blocker, beta-Adrenergic,Blockers, beta-Adrenergic,Blocking Agent, beta-Adrenergic,Blocking Agents, beta-Adrenergic,Receptor Blockader, beta-Adrenergic,Receptor Blockaders, beta-Adrenergic,beta Adrenergic Antagonist,beta Adrenergic Antagonists,beta Adrenergic Blocker,beta Adrenergic Blockers,beta Adrenergic Blocking Agent,beta Adrenergic Blocking Agents,beta Adrenergic Receptor Blockader,beta Adrenergic Receptor Blockaders,beta Adrenoceptor Antagonist,beta Adrenoceptor Antagonists,beta Blockers, Adrenergic,beta-Antagonist, Adrenergic,beta-Antagonists, Adrenergic,beta-Receptor Blockader, Adrenergic,beta-Receptor Blockaders, Adrenergic
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia

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