Absence of calcium channels in neonatal rat aortic myocytes.
We have investigated whole-cell Ba2+ currents through Ca2+ channels (IBa) in single myocytes freshly isolated from the aortic media of neonatal (1-day-old) and adult (12-week-old) rats. In neonatal myocytes, (IBa) was undetectable even in presence of the dihydropyridine (DHP) agonist Bay K 8644. Binding of [3H]Nitrendipine on crude plasma membrane preparation of media confirmed the absence of DHP-receptors. By contrast, a robust DHP-sensitive 'L-type' IBa was recorded in adults which was consistent with the presence of specific [3H]Nitrendipine binding sites. In conclusion, neonatal aortic myocytes do not express any Ca2+ channels. The acquisition of L-type Ca2+ channels may be related to cell differentiation and acquisition of contractility during postnatal development.
Quignard
J F
JF
CRBM, CNRS, UPR 9008.INSERM U249, Route de Mende, BP 5051, F-34033 Montpellier Cedex, France.
Grazzini
E
E
Guillon
G
G
Harricane
M C
MC
Nargeot
J
J
Richard
S
S
D000375:Aging / Q000502:physiology; D000818:Animals; D000831:Animals, Newborn; D001011:Aorta; D015220:Calcium Channels / Q000172:deficiency* / Q000502:physiology*; D009131:Muscle, Smooth, Vascular / Q000737:chemistry* / Q000166:cytology*; D051381:Rats; D011921:Rats, Inbred WKY
D015220:Calcium Channels