Histamine directly gates a chloride channel in lobster olfactory receptor neurons

Biogenic amines mediate many types of intercellular communication in multicellular organisms. Heretofore, little direct evidence has indicated that biogenic amines produce intracellular responses other than by triggering the enzymatic production of second messengers. Our electrophysiological studies of lobster olfactory receptor neurons now reveal that one biogenic amine, histamine, can directly gate an ion channel. The channel responds to histamine concentrations of 1 μM or more, is permeable primarily to Cl^-, is more active at depolarized potentials, and has a conductance of 44 pS in the American lobster and 66 pS in the Caribbean spiny lobster. The expression of this ligand-gated channel in olfactory receptor neurons implies that these neurons are targets of a regulatory or feedback process.