Evidence for a multiple innervation of subcommissural ependymocytes in the rat.

Glandular ependymocytes of the rat subcommissural organ (SCO) receive a multiple innervation: a serotonergic afference identified by radioautography and at least one other input of a hitherto unknown transmitter content. Both types of terminals make well differentiated axo-glandular synapses with SCO-ependymocytes, but display different morphological characteristics. Serotonergic terminals being considered as inhibitory, it is suggested that the other type of terminal is excitatory.