Changes in purinergic responses of the rabbit isolated central ear artery after chronic electrical stimulation in vivo.
1. The effect of chronic (4-16 days) electrical stimulation (5 Hz, 0.3 ms, 4-10 V) of the great auricular nerve in vivo on sympathetic cotransmission in the rabbit isolated central ear artery was examined. 2. Chronic stimulation had no significant effect on frequency-dependent (4-60 Hz) neurogenic contractions or contractile responses induced by exogenous noradrenaline (0.1-300 microM). 3. In contrast, contractions induced by exogenous alpha, beta-methylene ATP (10.0 microM) were significantly decreased in preparations from 16-day stimulated animals in comparison with sham-operated, 4-day and 8-day chronically stimulated animal groups. 4. It is concluded that chronic electrical stimulation of nerves supplying the ear artery may lead to the selective alteration of postjunctional P2x-purinoceptor mechanisms, while the effects mediated by post-junctional alpha 1-adrenoceptors remain unchanged.
Maynard
K I
KI
Department of Anatomy and Developmental Biology, University College London.
Loesch
A
A
Burnstock
G
G
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001158:Arteries / Q000187:drug effects / Q000294:innervation / Q000502:physiology; D004431:Ear, External / Q000098:blood supply / Q000294:innervation; D004558:Electric Stimulation; D004566:Electrodes; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000294:innervation / Q000378:metabolism*; D009638:Norepinephrine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D011817:Rabbits; D011983:Receptors, Purinergic / Q000187:drug effects*; D013564:Sympathetic Nervous System / Q000187:drug effects; D009435:Synaptic Transmission / Q000187:drug effects
D011983:Receptors, Purinergic; D011189:Potassium Chloride; D000255:Adenosine Triphosphate; C002630:alpha,beta-methyleneadenosine 5'-triphosphate; D009638:Norepinephrine