%0 Journal Article %A CARLOS BARAJAS-LÓPEZ %A ROSA ESPINOSA-LUNA %A VLADIMIR GERZANICH %T ATP Closes a Potassium and Opens a Cationic Conductance through Different Receptors in Neurons of Guinea Pig Submucous Plexus %D 1994 %J Journal of Pharmacology and Experimental Therapeutics %P 1396-1402 %V 268 %N 3 %X Intracellular recordings were made to study the actions of ATP and related nucleotides on neurons from the guinea pig submucous plexus. Local application of ATP, by pressure, induced a depolarization in most AH-type neurons, which had a latency of several milliseconds, lasted for about 5 sec, appeared to reverse at about +4 mV and occurred concomitantly with a reduction in input resistance. Pressure application of ATP also depolarized the S-type neurons. In most of these cells the depolarization had two phases: the first component resembled the depolarization observed in AH cells and the second component was much slower in onset and was longer lasting (30-90 sec). The slower component was associated with an increase in input resistance, reversed polarity near the potassium equilibrium potential and was observed in isolation in 30% of S neurons. Superfusion of ATP or other analogs(0.03-10 µm) induced a slow depolarization in most of S neurons with the following rank order of potency: 2-methylthio-ATP > ATP > adenosine-5'-o-3-thiotriphosphate = ADP; α,β-methylene ATP and β,γ-methylene ATP were inactive (10-100 µM). When whole-cell recordings were used, fast superfusion with ATP or other analogs (3-1000 µM) evoked, at negative membrane potentials, a rapidly desensitizing inward current. This current reversed Polarity at about 0 mV and was much reduced in low extracellular sodium concentration. The rank order of potency of the used agonists was: ATP = adenosine-5' -o-3-thiotriphosphate = 2-methylthio-ATP » α,β-methylene ATP = β,γ-methylene ATP; adenosine, AMP or ADP (1 mM) were inactive. ATP induced the appearance of unitary currents in outside-out patches with a single-channel conductance of about 15 picosiemens. In conclusion, ATP induced two types of depolarizations mediated by different receptors and ionic mechanisms. 1994 by The American Society for Pharmacology and Experimental Therapeutics %U https://jpet.aspetjournals.org/content/jpet/268/3/1396.full.pdf