Increased store-operated Ca2+ entry into contractile vascular smooth muscle following organ culture.
Ca2+ inflow via store-operated Ca2+ channels was investigated in rings of rat tail and basilar arteries kept in serum-free organ culture, which is known to preserve the contractility of the vascular smooth muscle. After culture for 3-4 days, Ca2+ release from intracellular stores in response to caffeine (20 mM) was augmented 2- to 4-fold. Following depletion of intracellular Ca2+ stores by caffeine and thapsigargin (10 microM), addition of Ca2+ (2.5 mM) caused an increase in the intracellular Ca2+ concentration which was 2-3 times greater in cultured than in freshly dissected rings, and was not affected by verapamil (10 microM). In contrast, L-type Ca2+ channel currents were decreased by 20% after culture. While freshly dissected rings developed no or very little force in response to the addition of Ca2+ after store depletion, cultured rings developed 42% (tail artery) and 60% (basilar artery) of the force of high-K+-induced contractions. These contractions in cultured vessels were insensitive to verapamil but could be completely relaxed by SKF-96365 (30 microM). Store depletion by caffeine increased the Mn2+ quench rate 3- to 4-fold in freshly dissected as well as cultured tail artery, while there was no increase in freshly dissected basilar artery, but a 3-fold increase in cultured basilar artery. Uptake of Ca2+ into intracellular stores was twice as rapid in cultured as in freshly dissected tail artery. This study shows that organ culture of vascular smooth muscle tissue causes changes in Ca2+ handling, resembling the pattern seen in dedifferentiating smooth muscle cells in culture, although contractile properties are maintained.
Dreja
K
K
Department of Physiological Sciences, Lund University, Lund, Sweden.
Bergdahl
A
A
Hellstrand
P
P
D000818:Animals; D001488:Basilar Artery; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000502:physiology; D020746:Calcium Channels, L-Type / Q000502:physiology; D016895:Culture Media, Serum-Free; D004553:Electric Conductivity; D005260:Female; D007093:Imidazoles / Q000494:pharmacology; D008345:Manganese / Q000378:metabolism; D009119:Muscle Contraction; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D009924:Organ Culture Techniques; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013623:Tail / Q000098:blood supply; D019284:Thapsigargin / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D020746:Calcium Channels, L-Type; D016895:Culture Media, Serum-Free; D007093:Imidazoles; D002110:Caffeine; D008345:Manganese; D019284:Thapsigargin; D014700:Verapamil; C063159:1-(2-(3-(4-methoxyphenyl)propoxy)-4-methoxyphenylethyl)-1H-imidazole; D011188:Potassium; D002118:Calcium