Biomaterial Database

Influence of the renin-angiotensin system on sympathetic neurotransmission in canine skeletal muscle in vivo. 1991

J H Schwieler, and T Kahan, and J Nussberger, and P Hjemdahl

Department of Pharmacology, Karolinska Institutet, Stockholm, Sweden.

The physiological importance of interactions between angiotensin II and sympathetic neurotransmission was studied in an in vivo model with constant flow blood perfused gracilis muscle in situ in dogs pretreated with desipramine and atropine. Sympathetic nerve stimulation-(2 and 8 Hz, 480 pulses) evoked over-flow of endogenous noradrenaline and vasoconstriction, and vasoconstrictor responses to exogenous noradrenaline (0.5 nmol, locally i.a.) were evaluated. Angiotensin converting enzyme inhibition by benazeprilat (10 mg i.v.; n = 8) reduced arterial angiotensin II levels from 26 +/- 8 to 2 +/- 1 pM and reduced mean arterial and basal muscle perfusion pressures. Subsequent resubstitution of angiotensin II (3, 30 and 90 ng kg-1 min-1 i.v.) elevated arterial angiotensin II dose-dependently (to 67 +/- 14, 622 +/- 63 and 1940 +/- 251 pM, respectively), as well as mean arterial and muscle perfusion pressures. Nerve stimulation-evoked noradrenaline overflow was unchanged following benazeprilat (-4 +/- 4 and +1 +/- 8% at 2 and 8 Hz, respectively) and during subsequent infusions of angiotensin II. Vasoconstrictor responses to nerve stimulation and exogenous noradrenaline were also uninfluenced by these treatments. Thus, angiotensin II did not enhance sympathetic neurotransmission at the postjunctional level. Another group of animals was pretreated with noncompetitive alpha-adrenoceptor blockade locally by phenoxybenzamine and benextramine (0.5 mg kg-1 i.a. of each; n = 7), which abolished vasoconstrictor responses to nerve stimulation. The effects of benazeprilat and subsequent angiotensin II infusions (3 and 30 ng kg-1 min-1 i.v.) on circulating angiotensin II levels, mean arterial and muscle perfusion pressures were similar in this group.(ABSTRACT TRUNCATED AT 250 WORDS)

UI	MeSH Term	Description	Entries
D009132	Muscles	Contractile tissue that produces movement in animals.	Muscle Tissue,Muscle,Muscle Tissues,Tissue, Muscle,Tissues, Muscle
D009435	Synaptic Transmission	The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.	Neural Transmission,Neurotransmission,Transmission, Neural,Transmission, Synaptic
D010643	Phenoxybenzamine	An alpha-adrenergic antagonist with long duration of action. It has been used to treat hypertension and as a peripheral vasodilator.	Dibenylene,Dibenyline,Dibenziran,Dibenzylin,Dibenzyline,Dibenzyran,Phenoxybenzamine Hydrochloride,Hydrochloride, Phenoxybenzamine
D012084	Renin-Angiotensin System	A BLOOD PRESSURE regulating system of interacting components that include RENIN; ANGIOTENSINOGEN; ANGIOTENSIN CONVERTING ENZYME; ANGIOTENSIN I; ANGIOTENSIN II; and angiotensinase. Renin, an enzyme produced in the kidney, acts on angiotensinogen, an alpha-2 globulin produced by the liver, forming ANGIOTENSIN I. Angiotensin-converting enzyme, contained in the lung, acts on angiotensin I in the plasma converting it to ANGIOTENSIN II, an extremely powerful vasoconstrictor. Angiotensin II causes contraction of the arteriolar and renal VASCULAR SMOOTH MUSCLE, leading to retention of salt and water in the KIDNEY and increased arterial blood pressure. In addition, angiotensin II stimulates the release of ALDOSTERONE from the ADRENAL CORTEX, which in turn also increases salt and water retention in the kidney. Angiotensin-converting enzyme also breaks down BRADYKININ, a powerful vasodilator and component of the KALLIKREIN-KININ SYSTEM.	Renin-Angiotensin-Aldosterone System,Renin Angiotensin Aldosterone System,Renin Angiotensin System,System, Renin-Angiotensin,System, Renin-Angiotensin-Aldosterone
D004285	Dogs	The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)	Canis familiaris,Dog
D004558	Electric Stimulation	Use of electric potential or currents to elicit biological responses.	Stimulation, Electric,Electrical Stimulation,Electric Stimulations,Electrical Stimulations,Stimulation, Electrical,Stimulations, Electric,Stimulations, Electrical
D005260	Female		Females
D000806	Angiotensin-Converting Enzyme Inhibitors	A class of drugs whose main indications are the treatment of hypertension and heart failure. They exert their hemodynamic effect mainly by inhibiting the renin-angiotensin system. They also modulate sympathetic nervous system activity and increase prostaglandin synthesis. They cause mainly vasodilation and mild natriuresis without affecting heart rate and contractility.	ACE Inhibitor,ACE Inhibitors,Angiotensin Converting Enzyme Inhibitor,Angiotensin I-Converting Enzyme Inhibitor,Angiotensin-Converting Enzyme Inhibitor,Kininase II Inhibitor,Kininase II Inhibitors,Angiotensin I-Converting Enzyme Inhibitors,Angiotensin-Converting Enzyme Antagonists,Antagonists, Angiotensin-Converting Enzyme,Antagonists, Kininase II,Inhibitors, ACE,Inhibitors, Angiotensin-Converting Enzyme,Inhibitors, Kininase II,Kininase II Antagonists,Angiotensin Converting Enzyme Antagonists,Angiotensin Converting Enzyme Inhibitors,Angiotensin I Converting Enzyme Inhibitor,Angiotensin I Converting Enzyme Inhibitors,Antagonists, Angiotensin Converting Enzyme,Enzyme Antagonists, Angiotensin-Converting,Enzyme Inhibitor, Angiotensin-Converting,Enzyme Inhibitors, Angiotensin-Converting,II Inhibitor, Kininase,Inhibitor, ACE,Inhibitor, Angiotensin-Converting Enzyme,Inhibitor, Kininase II,Inhibitors, Angiotensin Converting Enzyme
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
D001552	Benzazepines	Compounds with BENZENE fused to AZEPINES.