Szocik, “Calcium current in smooth muscle cells from normotensive and genetically hypertensive rats

Abstract Genetic hypertension results from numerous phe-notypic expressions. We hypothesized that increased calcium current in vascular smooth muscle of genetically hypertensive animals is partly responsible for observed increases in agonist sensitivity, contractility, and calcium influx. Using adult, spon-taneously hypertensive stroke-prone rats (SHRSP) and normo-tensive Wistar-Kyoto (WKY) controls from an inbred colony, we characterized calcium current in smooth muscle cells iso-lated from cerebral arteries. Calcium current in WKY cells reached a maximum of-21.1 ±2.1 pA (n=32) at +20 mV. Peak inward current at +20 mV in SHRSP cells had a mean amplitude of-44.4±3.0 pA (n=72, P<.05). SHRSP cells exhibited a higher calcium current density. Maximal inward current normalized to cell capacitance yielded mean values of 2.07±0.11 pA/pF for WKY (n=32) and 2.80+0.12 pA/p