[Presynaptic inhibitory action of type E prostaglandins on the cholinergic endings of the superior cervical ganglion in the guinea pig].

PGE1 10(-7) M reversibly inhibits impulse transmission at the synapses of the guinea-pig isolated superior cervical ganglion. Neither resting potential nor membrane resistance of the sympathetic neurons were affected by PGE treatment. Quantal analysis of transmitter release shows that in the presence of PGs the quantum size is not significantly changed while the quantum content appears to be consistently reduced. It is suggested that PGE modulates synaptic transmission in the guinea-pig superior cervical ganglion by inhibiting acetylcholine release from presynaptic terminals.