Gender-dependent difference in cell calcium handling in VSMC isolated from SHR: the effect of angiotensin II.
OBJECTIVE
To investigate gender-dependent difference in the free cytosolic calcium concentration ([Ca2+ ]i ) response to angiotensin II (Ang II) in vascular smooth muscle cells (VSMC) isolated from spontaneously hypertensive rats (SHR). To further evaluate this gender-dependent difference by studying the role of thapsigargin-sensitive intracellular calcium stores and calcium influx in VSMC isolated from male and female SHR.


METHODS
Confluent primary cultures of VSMC isolated from male (n = 14) and female (n = 14) SHR aged 10 weeks were used in this study. [Ca2+ ]i was measured by image analysis of single myocytes loaded with Fura-2. [Ca2+ ]i response of VSMC to Ang II was measured in the presence and absence of extracellular Ca2+, to evaluate the influence of Ca2+ influx. To characterize inositol triphosphate (IP3 )-sensitive sarcoplasmic reticulum calcium stores, thapsigargin-sensitive calcium stores were measured in VSMC isolated from SHR of both genders.


RESULTS
VSMC isolated from male SHR were characterized by an augmented [Ca2+ ]i response to angiotensin II in comparison with VSMC isolated from female SHR. Surprisingly, the thapsigargin-stimulated [Ca2+ ]i rise was found to be significantly greater in VSMC isolated from female SHR compared with VSMC isolated from male SHR. On the other hand, the gender-dependent difference in [Ca2+ ]i response to angiotensin II was abolished in the absence of extracellular calcium.


CONCLUSIONS
We demonstrated in VSMC isolated from SHR of both genders that a greater [Ca2+ ]i response to angiotensin II in male than female VSMC is dependent on Ca2+ influx.
Loukotová
Jana
J
Institute of Physiology, Academy of Sciences of the Czech Republic and Center for Experimental Research of Cardiovascular Diseases, Prague, Czech Republic. loukot@biomed.cas.cz
Kunes
Jaroslav
J
Zicha
Josef
J
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure; D002118:Calcium / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005110:Extracellular Space / Q000378:metabolism; D005260:Female; D006973:Hypertension / Q000378:metabolism; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011918:Rats, Inbred SHR; D012727:Sex Characteristics; D019284:Thapsigargin / Q000494:pharmacology; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
D004791:Enzyme Inhibitors; D014662:Vasoconstrictor Agents; D000804:Angiotensin II; D019284:Thapsigargin; D002118:Calcium