Voltage-dependent Ca2+ channels in resistance arteries from Dahl salt-sensitive rats.
To determine whether chronic salt-loading would alter voltage-dependent Ca2+ channels in resistance arteries of Dahl salt-sensitive rats, whole-cell voltage-clamp experiments were performed on single cells that were isolated from small mesenteric arteries. Dahl salt-sensitive rats were fed either an 8% NaCl diet (high-NaCl group) or a 0.3% NaCl diet (low-NaCl group) from the age of 6 or 7 weeks. After 4 to 5 weeks, systolic blood pressure was significantly higher in the high-NaCl group than in the low-NaCl group. In the high-NaCl group, the threshold potential for Ca2+ channel current was more negative and the current amplitude that was normalized by cell capacitance was higher at negative command potentials (-40 mV to -20 mV), as compared with the low-NaCl group. When the current was separated into fast transient current and slow sustained (L-type) current, the alteration in the high-NaCl group was attributable to the change in L-type current. The steady-state inactivation curve was not different between the high-NaCl and low-NaCl groups. In conclusion, L-type Ca2+ channels in resistance arteries of Dahl salt-sensitive rats became more available for opening near the resting potential after dietary salt-loading.
Ohya
Y
Y
Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Fujii
K
K
Eto
K
K
Abe
I
I
Fujishima
M
M
D000818:Animals; D020746:Calcium Channels, L-Type / Q000378:metabolism* / Q000502:physiology; D004039:Diet, Sodium-Restricted; D004553:Electric Conductivity; D004594:Electrophysiology; D008297:Male; D008638:Mesenteric Arteries / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism; D018408:Patch-Clamp Techniques; D051381:Rats; D020303:Rats, Inbred Dahl; D014655:Vascular Resistance
D020746:Calcium Channels, L-Type