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Inhibition of purinergic transmission by prostaglandin E 1 and E 2 in the guinea‐pig vas deferens: an electrophysiological study
Author(s) -
Brock James A.,
Cunnane Thomas C.
Publication year - 1996
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1996.tb15467.x
Subject(s) - vas deferens , excitatory postsynaptic potential , guinea pig , stimulation , electrophysiology , inhibitory postsynaptic potential , purinergic receptor , medicine , chemistry , endocrinology , extracellular , prostaglandin e , biochemistry
1 The effects of prostaglandin E 1 (PGE 1 ) and E 2 (PGE 2 ) on postjunctional electrical activity in the guinea‐pig vas deferens evoked by sympathetic nerve stimulation were investigated using both intracellular and focal extracellular recording techniques in vitro . 2 Bath application of PGE 1 (1–100 nM) or PGE 2 (0.1–100 nM) concentration‐dependently inhibited the amplitudes of all excitatory junction potentials (e.j.ps) evoked during short trains of stimuli (10 stimuli at 1 Hz). Increasing the duration of nerve stimulation (100 stimuli at 1 Hz) did not overcome this inhibitory effect. At these concentrations PGE 1 and PGE 2 were without any apparent inhibitory effect on the amplitudes of spontaneous e.j.ps. 3 Local application of PGE 1 (10–100 nM) or PGE 2 (10–30 nM) markedly reduced the frequency of occurrence of excitatory junction currents (e.j.cs) evoked by trains of 20–100 stimuli at 1 to 4 Hz without changing the amplitudes of spontaneous e.j.cs or the configuration of the nerve terminal impulse. 4 In the presence of PGE 1 or PGE 2 , raising the frequency of stimulation (from 1 to 4 Hz), increased the likelihood of e.j.c. occurrence. 5 The postjunctional electrical activity recorded in the guinea‐pig vas deferens is believed to be due to ATP released from the sympathetic nerve endings. Thus the present study demonstrates that both PGE 1 and PGE 2 powerfully inhibit quantal ATP release in the guinea‐pig vas deferens.