Effects of calcium antagonists on isolated bovine cerebral arteries: inhibition of constriction and calcium-45 uptake induced by potassium or serotonin

Journal Article · Fri May 01 00:00:00 EDT 1987 · Stroke; (United States)

DOI:https://doi.org/10.1161/01.STR.18.3.591· OSTI ID:6478486

Wendling, W W; Harakal, C

The purpose of this study was to determine the mechanisms by which organic calcium channel blockers inhibit cerebral vasoconstriction. Isolated bovine middle cerebral arteries were cut into rings to measure contractility or into strips to measure radioactive calcium (/sup 45/Ca) influx and efflux. Calcium channel blockers (10(-5) M verapamil or 3.3 X 10(-7) M nifedipine) and calcium-deficient solutions all produced near-maximal inhibition of both potassium- and serotonin-induced constriction. In calcium-deficient solutions containing potassium or serotonin, verapamil and nifedipine each blocked subsequent calcium-induced constriction in a competitive manner. Potassium and serotonin significantly increased /sup 45/Ca uptake into cerebral artery strips during 5 minutes of /sup 45/Ca loading; for potassium /sup 45/Ca uptake increased from 62 to 188 nmol/g, and for serotonin from 65 to 102 nmol/g. Verapamil or nifedipine had no effect on basal /sup 45/Ca uptake but significantly blocked the increase in /sup 45/Ca uptake induced by potassium or serotonin. Potassium, and to a lesser extent serotonin, each induced a brief increase in the rate of /sup 45/Ca efflux into calcium-deficient solutions. Verapamil or nifedipine had no effect on basal or potassium-stimulated /sup 45/Ca efflux. The results demonstrate that verapamil and nifedipine block /sup 45/Ca uptake through both potential-operated (potassium) and receptor-operated (serotonin) channels in bovine middle cerebral arteries.

• Research Organization: Temple Univ. School of Medicine, Philadelphia, PA
• OSTI ID: 6478486
• Journal Information: Stroke; (United States), Vol. 3
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CALCIUM
MEMBRANE TRANSPORT
CEREBRAL ARTERIES
VASOCONSTRICTION
POTASSIUM
BIOCHEMICAL REACTION KINETICS
SEROTONIN
BIOLOGICAL FUNCTIONS
CALCIUM 45
CATTLE
IN VITRO
INHIBITION
TRACER TECHNIQUES
ALKALI METALS
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METALS
AMINES
ANIMALS
AROMATICS
ARTERIES
AUTONOMIC NERVOUS SYSTEM AGENTS
AZAARENES
AZOLES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BLOOD VESSELS
BODY
CALCIUM ISOTOPES
CARDIOVASCULAR SYSTEM
DAYS LIVING RADIOISOTOPES
DOMESTIC ANIMALS
DRUGS
ELEMENTS
EVEN-ODD NUCLEI
FUNCTIONS
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
INDOLES
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MAMMALS
METALS
NEUROREGULATORS
NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PYRROLES
RADIOISOTOPES
RADIOPROTECTIVE SUBSTANCES
REACTION KINETICS
RUMINANTS
SYMPATHOMIMETICS
TRYPTAMINES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques