Effect of JTH-601, a putative α 1L-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.