Spontaneous oscillations in cytoplasmic free calcium concentration in vascular smooth muscle: a potential mechanism associated with myogenic tone.
1. The cytoplasmic free calcium concentration was monitored in primary rat aortic smooth muscle cells, grown in culture and serum-deprived for 24-48 h, with the calcium sensitive fluoroprobe, Fura-2. 2. In the absence of external stimuli, spontaneous increases in the cytoplasmic free calcium concentration were observed which averaged 60 +/- 11 nmol/l and lasted approximately 30 s. 3. The calcium transients were in part dependent on intracellular calcium and were abolished when the temperature was lowered to 10 degrees C. 4. It is concluded that vascular smooth muscle cells have an inherent ability to initiate spontaneous transient increases in cytoplasmic free calcium concentration via membrane calcium channels.
Bobik
A
A
Clinical Research Unit, Alfred Hospital, Prahran, Victoria, Australia.
Weissberg
P L
PL
Little
P J
PJ
D000818:Animals; D001011:Aorta / Q000166:cytology / Q000187:drug effects; D001572:Benzofurans; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D016257:Fura-2; D066298:In Vitro Techniques; D009129:Muscle Tonus / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013050:Spectrometry, Fluorescence
D001572:Benzofurans; D015220:Calcium Channels; D002118:Calcium; D016257:Fura-2