Noriaki Tanimitsu

Effect of JTH-601, a putative α1L-adrenoceptor antagonist, on guinea pig nasal mucosa vasculature

Abstract The existence of α 1 -adrenoceptors with low affinity for prazosin, an α 1L subtype, has been proposed in addition to α 1 -adrenoceptor subtypes with high affinity for prazosin, i.e. the α 1H group: α 1A , α 1B and α 1D subtypes. In the present study, we investigated the effect of JTH-601 (3-( N -[2-(4-hydroxy-2-isopropyl-5-methylphenoxy)ethyl]- N -methylaminomethyl)-4-methoxy-2,5,6-trimethylphenol hemifumarate), a putative α 1L -adrenoceptor antagonist, on the isolated guinea pig nasal mucosa vasculature. JTH-601 (0.01–0.03 μM) competitively antagonized the noradrenaline-induced contraction of the tissue in a concentration-dependent manner. The p A 2 value for JTH-601 was 8.14±0.04 (means±SEM, n =6). The data suggests that the α 1L -subtype is involved in the noradrenaline-induced contraction of the guinea pig nasal mucosa vasculature.