An electrophysiological analysis of the actions of prostaglandin on neuromuscular transmission in the guinea‐pig vas deferens.

Abstract

SUMMARYEffects of prostaglandins (PGs) on the neuromuscular junction of the guinea-pig vas deferens were investigated by the micro-electrode and double sucrose gap methods.1. PGE1, PGE2 or PGF20 (10-10 to 10-7 g/ml.) did not change the membrane potential, membrane resistance and electrical threshold required to produce the action potential.2. PGs markedly suppressed the amplitude of excitatory junction potential (e.j.p.) but the facilitation phenomena seen with repetitive stimulation were not affected. PGs did not change the amplitude and frequency of the miniature e.j.p.3. The action potential recorded from the small nerve bundle with the aid of an extracellular micro-electrode method was not affected by PGs. 4. 6. Indomethacin (10-6 g/ml.) had no effect on the amplitudes of e.j.p. produced by repetitive stimulation.7. These results indicate that a low concentration of PGs interact with [Ca]o at the activated nerve terminals, but that there is no modification of the actions of Ca in the nerve terminals required for release of chemical transmitter.

Actions of indomethacin and prostaglandins on neuroeffector transmission in the dog trachea

“…In the preparations of vas deferens or ileal longitudinal muscle of guinea-pig there was no such reduction in the amplitude, and evidence of a steady level was apparent within 1 hr after the start of experiments (Ito & Tajima, 1979, 1980. Field stimulations activated both cholinergic and adrenergic nerve fibres in this preparation.…”

Action of morphine on the neuro‐effector transmission in the guinea‐pig ileum and in the mouse vas deferens.

“…ITO AND K. TAJIMA Effect of morphine on the junction potentials of mouse vas deferens The effects of morphine on the neuro-effector juncion of mouse or guinea-pig vas deferens were observed using the double sucrose gap and micro-electrode methods (Ito & Tajima, 1979 At concentrations over 10-8 M, morphine showed strong blocking action on the e.j.p. of mouse vas deferens recorded by either the sucrose gap or microelectrode method.…”

“…To analyse the effects of morphine, growth in the amplitude of the e.j.p. during the repetitive stimulation was predicted by the method introduced by Mallart & Martin (1967), on the neuromuscular junction in the frog end-plate, and also that in the guinea-pig vas deferens by Ito & Tajima (1979). Fig.…”

“…of mouse vas deferens, compound action potentials were recorded from the sympathetic nerve trunk which innervates the vas deferens, using the micro-electrode extracellularly (Ito & Tajima, 1979). The micro-electrode was allowed to penetrate the sympathetic nerve bundles (10-30 sam).…”

The Effects of Substance P on Smooth Muscle Cells and on Neuro‐effector Transmission in the Guinea‐pig Ileum

“…The double sucrose gap, used to record membrane potential and tension development included the tissue chamber described by Ito & Tajima (1979 The bathing solution was kept at room temperature (23-27°C), as under these conditions the frequency of the spontaneous spike discharges was relatively low, and the effects of SP on the membrane potential could be readily observed.…”