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Augmented calcium currents in mesenteric artery branches of the spontaneously hypertensive rat.
Hypertension. 1995 Dec; 26(6 Pt 2):1060-4.H

Abstract

The greater efficacy of organic channel blockers in lowering peripheral resistance and blood pressure in hypertensive subjects has been suggested to be the result of augmented calcium influx through L-type calcium channels in arterial smooth muscle. These studies were performed to determine whether differences exist in voltage-gated calcium channels of mesenteric artery branches from 20-week-old spontaneously hypertensive rats (SHR) compared with Wistar-Kyoto rats (WKY). Single myocytes were acutely isolated by collagenase and elastase treatment and studied at room temperature (approximately 20 degrees C) with the use of whole-cell, patch-clamp methods. Maximum values of calcium current measured at 0 mV from a holding potential of -90 mV were larger in SHR myocytes (105 +/- 11 versus 149 +/- 15 pA). Values of cell capacitance were smaller in SHR (29.5 +/- 1.3 pF) compared with WKY (35.0 +/- 1.5 pF) myocytes. Cell capacitance measures surface membrane area and, when used to normalize calcium currents, magnified the difference between WKY and SHR to approximately 47%. There was a larger percent reduction of maximum calcium current at holding potentials of -60 and -40 mV in SHR compared with WKY myocytes: for example, at -40 mV calcium current was reduced from values at -90 mV by -73 +/- 2% in SHR compared with -58 +/- 1% in WKY. When divided by the maximum current for each holding potential, the voltage dependence of normalized calcium currents for the two groups was completely superimposed. Difference currents were calculated by subtracting currents measured from holding potentials of -90 and -40 mV. The voltage dependence of difference currents was identical to that of the calcium currents measured from the two values of holding potential.(

ABSTRACT

TRUNCATED AT 250 WORDS)

Authors+Show Affiliations

Bockus Research Institute, Graduate Hospital, Philadelphia, PA 19146, USA.No affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

7498968

Citation

Cox, R H., and I M. Lozinskaya. "Augmented Calcium Currents in Mesenteric Artery Branches of the Spontaneously Hypertensive Rat." Hypertension (Dallas, Tex. : 1979), vol. 26, no. 6 Pt 2, 1995, pp. 1060-4.
Cox RH, Lozinskaya IM. Augmented calcium currents in mesenteric artery branches of the spontaneously hypertensive rat. Hypertension. 1995;26(6 Pt 2):1060-4.
Cox, R. H., & Lozinskaya, I. M. (1995). Augmented calcium currents in mesenteric artery branches of the spontaneously hypertensive rat. Hypertension (Dallas, Tex. : 1979), 26(6 Pt 2), 1060-4.
Cox RH, Lozinskaya IM. Augmented Calcium Currents in Mesenteric Artery Branches of the Spontaneously Hypertensive Rat. Hypertension. 1995;26(6 Pt 2):1060-4. PubMed PMID: 7498968.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Augmented calcium currents in mesenteric artery branches of the spontaneously hypertensive rat. AU - Cox,R H, AU - Lozinskaya,I M, PY - 1995/12/1/pubmed PY - 1995/12/1/medline PY - 1995/12/1/entrez SP - 1060 EP - 4 JF - Hypertension (Dallas, Tex. : 1979) JO - Hypertension VL - 26 IS - 6 Pt 2 N2 - The greater efficacy of organic channel blockers in lowering peripheral resistance and blood pressure in hypertensive subjects has been suggested to be the result of augmented calcium influx through L-type calcium channels in arterial smooth muscle. These studies were performed to determine whether differences exist in voltage-gated calcium channels of mesenteric artery branches from 20-week-old spontaneously hypertensive rats (SHR) compared with Wistar-Kyoto rats (WKY). Single myocytes were acutely isolated by collagenase and elastase treatment and studied at room temperature (approximately 20 degrees C) with the use of whole-cell, patch-clamp methods. Maximum values of calcium current measured at 0 mV from a holding potential of -90 mV were larger in SHR myocytes (105 +/- 11 versus 149 +/- 15 pA). Values of cell capacitance were smaller in SHR (29.5 +/- 1.3 pF) compared with WKY (35.0 +/- 1.5 pF) myocytes. Cell capacitance measures surface membrane area and, when used to normalize calcium currents, magnified the difference between WKY and SHR to approximately 47%. There was a larger percent reduction of maximum calcium current at holding potentials of -60 and -40 mV in SHR compared with WKY myocytes: for example, at -40 mV calcium current was reduced from values at -90 mV by -73 +/- 2% in SHR compared with -58 +/- 1% in WKY. When divided by the maximum current for each holding potential, the voltage dependence of normalized calcium currents for the two groups was completely superimposed. Difference currents were calculated by subtracting currents measured from holding potentials of -90 and -40 mV. The voltage dependence of difference currents was identical to that of the calcium currents measured from the two values of holding potential.(ABSTRACT TRUNCATED AT 250 WORDS) SN - 0194-911X UR - https://www.unboundmedicine.com/medline/citation/7498968/Augmented_calcium_currents_in_mesenteric_artery_branches_of_the_spontaneously_hypertensive_rat_ L2 - https://www.ahajournals.org/doi/10.1161/01.hyp.26.6.1060?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -