Evoked noradrenaline release in the rabbit ear artery: enhancement by purines, attenuation by neuropeptide Y and lack of effect of calcitonin gene-related peptide.
1. Adenosine (30 microM) and its analogues 5'-N-ethylcarboxaminoadenosine (5 and 30 microM) and L-phenylisopropyladenosine (5 and 30 microM), potentiated the evoked but not spontaneous release of tritiated noradrenaline in the rabbit central ear artery. 2. Prejunctional inhibition of the evoked but not spontaneous release of tritiated noradrenaline by 100 nM neuropeptide Y is greater at 2 min than at 10 min after superfusion of the peptide. 3. Calcitonin gene-related peptide (2.63 to 263 nM) did not affect the evoked or spontaneous release of tritiated noradrenaline in this preparation. 4. These results are discussed in terms of prejunctional modulation of sympathetic transmission in the rabbit central ear artery.
Department of Anatomy and Developmental Biology, University College London.
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Maynard
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Burnstock
D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D019830:Adenosine-5'-(N-ethylcarboxamide); D000818:Animals; D001158:Arteries / Q000187:drug effects / Q000378:metabolism; D015740:Calcitonin Gene-Related Peptide / Q000494:pharmacology*; D004431:Ear, External / Q000098:blood supply; D066298:In Vitro Techniques; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D009478:Neuropeptide Y / Q000494:pharmacology*; D009638:Norepinephrine / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010660:Phenylisopropyladenosine / Q000494:pharmacology; D011687:Purines / Q000494:pharmacology*; D011817:Rabbits; D012039:Regional Blood Flow / Q000187:drug effects; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects; D013779:Tetrodotoxin / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
D009478:Neuropeptide Y; D011687:Purines; D014665:Vasodilator Agents; D010660:Phenylisopropyladenosine; D019830:Adenosine-5'-(N-ethylcarboxamide); D013779:Tetrodotoxin; D015740:Calcitonin Gene-Related Peptide; D000241:Adenosine; D009638:Norepinephrine