ROLE OF HISTAMINE AND HISTAMINERGIC AGENTS ON NORADRENALINE UPTAKE INSMOOTH-MUSCLE PREPARATIONS

It has been shown that adrenergic neurotransmission in different tissu es can be modified by histamine (HIST) but the mechanisms of this acti on have still not been fully clarified. This study aimed to demonstrat e the possible involvement of H-receptor H-receptor subtypes in the re alization of histamine inhibitory effects on smooth muscle tissues. HI ST 2-(2-aminoethyl)thiazole (AET) and dimaprit (DMP) exerted a similar inhibition of noradrenaline (NA)-uptake(1) in rat vas deferens and ra bbit ear artery. After H-1-blockade with mepyramine (MEP), HIST and DM P did not change the uptake(1) in rat vas deferens and decreased NA ne uronal accumulation in rabbit ear artery. The H-2-blockade with raniti dine (RAN) did not affect HIST- and AET-induced inhibition of NA-uptak e(1) in rat vas deferens and completely abolished it in rabbit ear art ery. These data suggest that different H-receptor subtypes might be in volved in HIST inhibitory action on NA neuronal uptake in both tissues . It appears, however that the inhibition of NA uptaker plays only a m inor role in the effects of HIST on smooth muscle contractions.