Gender-specific reduction in contractility and [Ca(2+)](i) in vascular smooth muscle cells of female rat
| Autor: | Raouf A. Khalil, Jason G. Murphy |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
Male
medicine.medical_specialty Contraction (grammar) Vascular smooth muscle Physiology Cell Separation Biology Rats Inbred WKY Muscle Smooth Vascular Potassium Chloride Contractility Phenylephrine Internal medicine Caffeine Rats Inbred SHR medicine Animals Vasoconstrictor Agents Castration Sex Characteristics Estradiol Osmolar Concentration Cell Biology Intracellular Membranes Rats medicine.anatomical_structure Endocrinology Vasoconstriction Calcium Female medicine.symptom Vascular smooth muscle contraction Blood vessel medicine.drug Muscle contraction |
| Zdroj: | American journal of physiology. Cell physiology. 278(4) |
| ISSN: | 0363-6143 |
| Popis: | The hypothesis that vascular protection in females and its absence in males reflects gender differences in [Ca2+]iand Ca2+mobilization mechanisms of vascular smooth muscle contraction was tested in fura 2-loaded aortic smooth muscle cells isolated from intact and gonadectomized male and female Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats. In WKY cells incubated in Hanks' solution (1 mM Ca2+), the resting length and [Ca2+]iwere significantly different in intact males (64.5 ± 1.2 μm and 83 ± 3 nM) than in intact females (76.5 ± 1.5 μm and 64 ± 7 nM). In intact male WKY, phenylephrine (Phe, 10−5M) caused transient increase in [Ca2+]ito 428 ± 13 nM followed by maintained increase to 201 ± 8 nM and 32% cell contraction. In intact female WKY, the Phe-induced [Ca2+]itransient was not significantly different, but the maintained [Ca2+]i(159 ± 7 nM) and cell contraction (26%) were significantly less than in intact male WKY. In Ca2+-free (2 mM EGTA) Hanks', Phe and caffeine (10 mM) caused transient increases in [Ca2+]iand contraction that were not significantly different between males and females. Membrane depolarization by 51 mM KCl caused 31% cell contraction and increased [Ca2+]ito 259 ± 9 nM in intact male WKY, which were significantly greater than a 24% contraction and 214 ± 8 nM [Ca2+]iin intact female WKY. Maintained Phe- and KCl-stimulated cell contraction and [Ca2+]iwere significantly greater in SHR than WKY in all groups of rats. Reduction in cell contraction and [Ca2+]iin intact females compared with intact males was significantly greater in SHR (∼30%) than WKY (∼20%). No significant differences in cell contraction or [Ca2+]iwere observed between castrated males, ovariectomized (OVX) females, and intact males, or between OVX females with 17β-estradiol implants and intact females. Exogenous application of 17β-estradiol (10−8M) to cells from OVX females caused greater reduction in Phe- and KCl-induced contraction and [Ca2+]iin SHR than WKY. Thus the basal, maintained Phe- and depolarization-induced [Ca2+]iand contraction of vascular smooth muscle triggered by Ca2+entry from the extracellular space exhibit differences depending on gender and the presence or absence of female gonads. Cell contraction and [Ca2+]idue to Ca2+release from the intracellular stores are not affected by gender or gonadectomy. Gender-specific reduction in contractility and [Ca2+]iin vascular smooth muscle of female rats is greater in SHR than WKY rats. |
| Databáze: | OpenAIRE |
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