“… amino acids l-phenylalanine , l-alanine, or l-tryptophan (all 1 mM) evoked inhibitory junction potentials (… ms, amplitude 3-8 mV, each n > 6) that were blocked by TTX and partially blocked by antagonists of P2X receptors and/or … antagonists at 5-HT(3) and 5-HT(4) receptors.”