Expression of ET(A) and ET(B) receptor mRNA in human cerebral arteries

The vascular effects of endothelins (ET) are in mammals mediated via two receptor subtypes, endothelin A (ET(A), mainly constrictive) and endothelin B (ET(B), mainly dilating) receptors. We have examined the presence of ET(A) and ET(B) receptor mRNA using the reverse transcription polymerase chain reaction (RT-PCR) in both normal human cerebral arteries and cerebral arteries from patients with cerebrovascular disease. Two vessel preparations were studied: macroscopic arteries and microvessels, the latter obtained through a sensitive separation method. In endothelial cells both ET(A) and ET(B) receptor mRNA was detected. In almost all samples from normal cerebral arteries only ET(A) receptor mRNA was detected, whereas in vessel samples from patients with cerebrovascular disease as well as cerebral neoplasms, additional ET(B) receptor mRNA was detected significantly more frequently. The pathophysiological significance of this difference is at present speculative, but does point to a vascular involvement of this receptor in cerebrovascular disease.