Hemolysate inhibits L-type Ca2+ channels in rat basilar smooth muscle cells.
Erythrocyte lysate increases intracellular Ca2+ ([Ca2+]i) and contracts cerebral arteries in vitro and has been suggested to be the cause for cerebral vasospasm. We investigated the effect of hemolysate on L-type Ca2+ channels directly by using patch clamp techniques in freshly isolated single smooth muscle cells from rat basilar artery. Patch clamp studies revealed a whole-cell current which resembles the L-type Ca2+ current reported by others. Hemolysate reduced the amplitude of the L-type Ca2+ channel current. The effect of hemolysate was reversible by washout and repeatable. Hemolysate was separated into two fractions by using filter membranes. The fraction > 1 kDa which contains oxyhemoglobin and other proteins mimicked the effect of hemolysate, while the fraction < 1 kDa and ATP were without effect. We conclude that hemolysate does not increase [Ca2+]i by activation of L-type Ca2+ channel.
Kim
C J
CJ
Department of Surgery, University of Chicago, Ill. 60637, USA.
Weir
B
B
Macdonald
R L
RL
Marton
L S
LS
Zhang
H
H
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000818:Animals; D001488:Basilar Artery / Q000166:cytology / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D004095:Dihydropyridines / Q000494:pharmacology; D004553:Electric Conductivity; D004912:Erythrocytes / Q000502:physiology*; D005260:Female; D006460:Hemolysin Proteins / Q000494:pharmacology; D006461:Hemolysis; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D004095:Dihydropyridines; D006460:Hemolysin Proteins; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester