The effect of 5'-N-ethylcarboxamideadenosine on the isolated hemidiaphragm of the rat during direct and indirect electrical stimulation.
Similar to adenosine and some of its derivatives, 5'-N-ethylcarboxamideadenosine (NECA) produced a biphasic effect on the isolated hemidiaphragm of the rat: a potentiation of the isometric contraction during direct electrical stimulation (in the presence of dipyridamole), and a depression during indirect electrical stimulation, and particularly so in a partially curarized preparation. The potentiating effect is presumed to be due to activation of the cAMP system, probably through A2 receptor sites, although a differentiation of the receptor subtype could not be made with aminophylline and XAC. Inhibition is most probably due to a depressant action of NECA on the acetylcholine release from the motor nerve terminals. These results accord with our previous findings, suggesting that adenosine may be part of a buffer system which participates in balancing the excitatory and inhibitory influences on skeletal muscle contraction.
Prostran
M
M
Department of Pharmacology, Faculty of Medicine, Belgrade, Yugoslavia.
Varagić
V M
VM
D000241:Adenosine / Q000494:pharmacology; D019830:Adenosine-5'-(N-ethylcarboxamide); D000628:Aminophylline / Q000494:pharmacology; D000818:Animals; D003964:Diaphragm / Q000187:drug effects; D004176:Dipyridamole / Q000494:pharmacology; D004558:Electric Stimulation; D005260:Female; D066298:In Vitro Techniques; D007537:Isometric Contraction / Q000187:drug effects; D008297:Male; D009466:Neuromuscular Blocking Agents / Q000494:pharmacology; D051381:Rats; D011983:Receptors, Purinergic / Q000187:drug effects; D012132:Respiratory Muscles / Q000187:drug effects* / Q000502:physiology; D014403:Tubocurarine / Q000494:pharmacology; D014970:Xanthines / Q000494:pharmacology
D009466:Neuromuscular Blocking Agents; D011983:Receptors, Purinergic; D014970:Xanthines; D000628:Aminophylline; D019830:Adenosine-5'-(N-ethylcarboxamide); D004176:Dipyridamole; C051869:8-(4-((2-aminoethyl)aminocarbonylmethyloxy)phenyl)-1,3-dipropylxanthine; D000241:Adenosine; D014403:Tubocurarine