On the transmitter at the A-to-B cell in Aplysia californica.

Cerebral A neurons make excitatory contact with cerebral B cells. While glutamate, histamine and serotonin all have excitatory receptors on B cells, the A-to-B cells synaptic potential was not found sensitive to curare, strychnine, antihistaminergic or antiserotoninergic drugs, nor did bath-perfused glutamate or serotonin cause desensitization of the synaptic response. We conclude that none of these candidates is the transmitter at this synapse.