Vasodilatation with pinacidil. Mode of action in rat resistance vessels

Journal Article · Fri Jan 01 04:00:00 EST 1988 · JDBP (Journal of Developmental and Behavioral Pediatrics); (USA)

DOI:https://doi.org/10.2165/00003495-198800367-00006· OSTI ID:5547370

Videbaek, L M; Aalkjaer, C; Mulvany, M J ^[1]

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1. Univ. of Aarhus (Denmark)

Pinacidil is a newly developed antihypertensive vasodilator, proposed to belong to the new group of smooth muscle relaxants, the K+ channel openers. The in vitro effects of pinacidil on induced tone, smooth muscle membrane potential and {sup 86}Rb and {sup 42}K efflux from rat resistance vessels (internal diameter about 200 microns) were studied. Tone induced with noradrenaline was concentration-dependently inhibited by pinacidil. Responses to electrical field stimulation were also inhibited. However, tone induced with high K+ depolarization, noradrenaline in the presence of high K+, caffeine-induced contractions and noradrenaline contractions in the presence of felodipine were little affected by pinacidil. Pinacidil caused concentration-dependent hyperpolarisation of the resting smooth muscle. Pinacidil caused only a small and transient increase of the {sup 86}Rb efflux rate constant, while the same concentrations of pinacidil produced a significant increase in the {sup 42}K efflux rate constant. Our results seem to indicate that the relaxant effect of pinacidil is the result of an increase in K+ permeability, thus causing hyperpolarisation and relaxation. The opened K+ channels appear to be selective for K+ over Rb+.

• OSTI ID: 5547370
• Journal Information: JDBP (Journal of Developmental and Behavioral Pediatrics); (USA), Journal Name: JDBP (Journal of Developmental and Behavioral Pediatrics); (USA); ISSN JDBPD; ISSN 0012-6667
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ADRENAL HORMONES
ALKALI METAL ISOTOPES
ALKALI METALS
ANIMALS
ANTIHYPERTENSIVE AGENTS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BLOOD VESSELS
BODY
CARBONIC ACID DERIVATIVES
CARDIOTONICS
CARDIOVASCULAR AGENTS
CARDIOVASCULAR SYSTEM
CELL CONSTITUENTS
CELL MEMBRANES
CONTRACTION
DAYS LIVING RADIOISOTOPES
DRUGS
ELEMENTS
GUANIDINES
HOURS LIVING RADIOISOTOPES
IN VITRO
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MAMMALS
MEMBRANES
METALS
MINUTES LIVING RADIOISOTOPES
MUSCLES
NEUROREGULATORS
NORADRENALINE
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PERMEABILITY
POTASSIUM
POTASSIUM 42
POTASSIUM ISOTOPES
RADIOISOTOPES
RATS
REACTION KINETICS
RODENTS
RUBIDIUM
RUBIDIUM 86
RUBIDIUM ISOTOPES
SYMPATHOMIMETICS
TRACER TECHNIQUES
VASODILATION
VASODILATORS
VERTEBRATES