Electrophysiological analysis of neurogenic vasodilatation in the isolated lingual artery of the XXXX .

@entity2997 @entity1022 @entity4524 @entity95 @entity1617 @entity3897 @entity2607 @entity1063 @entity934
The nature of neurogenic vasodilatation was investigated in isolated segments of @entity95 lingual artery. In separate experiments membrane responses to nerve stimulation were studied by use of microelectrodes. In the presence of @entity2997 to block constrictor responses and @entity1063 to induce tone, field stimulation with trains of pulses (8 Hz for 0.5 to 4 s) produced vasodilatation. @entity3897 (10(-6) M) reduced the relaxations to about 50% of the control values while the induced vasodilatations were potentiated by @entity2607 . @entity1022 ( @entity4524 , 10(-7) M) blocked all nerve-evoked responses. These data suggest that there is a cholinergic and a non-cholinergic component of the vasodilatation produced by nerve stimulation in the @entity95 lingual artery. Single stimuli did not evoke electrophysiological responses. With parameters similar to those used in the mechanical studies, periarterial stimulation in the presence of @entity2997 evoked membrane hyperpolarizations which achieved amplitudes of up to 11 mV. The ionophoretic application of @entity934 ( @entity1617 ) produced hyperpolarization. The inhibitory junction potentials (i.j.ps) but not the ionophoretic-induced responses were blocked by @entity4524 . The nerve-evoked and the @entity1617 -induced hyperpolarizations were potentiated by @entity2607 (5 X 10(-7) M) and totally blocked by @entity3897 (10(-7) M). I.j.ps and hyperpolarization to ionophoresis of @entity1617 were recorded from arteries in which the endothelium had been removed by mechanical rubbing. Mechanical relaxation to field stimulation and @entity1617 was observed in preparations without endothelium. These data suggest that the cholinergic component of the neurogenic vasodilatation in the @entity95 lingual artery is accompanied by hyperpolarization. The non-cholinergic component does not appear to possess an electrophysiological correlate. In addition, it seems that the action of nerve-released @entity1617 is mediated by muscarinic receptors which are situated directly on the vascular smooth muscle cells.
