Endothelin potentiates TRPV1 via ETA receptor-mediated activation of protein kinase C

Molecular Pain

Table 1 Synopsis of ET-1-mediated cAMP and inositol phosphate formation via ET_A and ET_B receptors

	HEK ET_AR		HEK ET_BR
	-fold of control	EC₅₀ [nM]	-fold of control	EC₅₀ [nM]
formation of inositol phosphates	22.3 ± 2.5	4.5 ± 1.2	18 ± 2.0	7.3 ± 1.7
formation of cAMP	34 ± 10.6	13.3 ± 3.2	n. i.	n.a.

HEK293 cells stably expressing the ET_AR or the ET_BR were stimulated with increasing concentrations of ET-1 (up to 100 nM) in the presence of 10 mM LiCl (inositol phosphate assays) for 60 min or 1 mM IBMX (cAMP assays) for 30 min. The amount of formed inositol phosphates was determined by anion exchange chromatography and cAMP was determined by cAMP RIA as described in Materials and Methods. Values are means ± SD of at least three independent experiments performed in duplicate. Duplicates differed by less than 10 %. n.i.: no increase, n.a.: not applicable

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