Effects of mepivacaine, prilocaine and lidocaine on the induced constriction of the maxillofacial vasculature of the rat.

Infusions of mepivacaine 5 or 50 micrograms.min-1 and prilocaine 50 micrograms.min-1 for 10 min into the maxillofacial arterial vasculature of the anaesthetized rat curtailed significantly rises in infusion pressure induced by the administration of adrenaline via the same route. The effect of mepivacaine was significantly greater than that of prilocaine. Such anti-constrictory action following intraluminal infusion, also shown by lidocaine in a previous study, contrasts with the variable (dilatory or constrictory) consequences of perivascular injections of the same local anaesthetics. Moreover, the equi-constrictory effects of (a) 1.10(-3) IU felypressin and (b) 120 ng adrenaline were attenuated to the same extent by lidocaine 5 micrograms.min-1 for 10 min, demonstrating that the anti-constrictory action of local anaesthetics is not specifically anti-adrenergic as has been suggested previously.