Enhancement of transmission at the frog neuromuscular junction by adenosine deaminase: evidence for an inhibitory role of endogenous adenosine on neuromuscular transmission.
Adenosine deaminase reversibly increased the amplitude and the quantum content of the end-plate potentials (EPPs) recorded from superficial muscle fibers of frog sartorius preparations in which twitches have been prevented with high-magnesium solutions. Adenosine deaminase prevented the inhibitory effect of exogenously applied adenosine but not that of 2-chloroadenosine on the amplitude of EPPs. The effect of adenosine deaminase was abolished by erythro-9(2-hydroxy-3-nonyl)adenine (EHNA). The results suggest that endogenous adenosine exerts an inhibitory 'tone' over neuromuscular transmission.
D000241:Adenosine / Q000502:physiology*; D000243:Adenosine Deaminase / Q000494:pharmacology*; D000818:Animals; D005071:Evoked Potentials / Q000187:drug effects; D009045:Motor Endplate / Q000187:drug effects*; D009469:Neuromuscular Junction / Q000187:drug effects* / Q000201:enzymology; D009700:Nucleoside Deaminases / Q000494:pharmacology*; D011895:Rana ridibunda; D009435:Synaptic Transmission / Q000187:drug effects*; D013997:Time Factors
D009700:Nucleoside Deaminases; D000243:Adenosine Deaminase; D000241:Adenosine