Detection of histamine binding sites (receptors) in Tetrahymena by fluorescence technique

Examinations with fluorescein isothiocyanate (FITC)-bovine serum albumin histamine conjugate and with FITC-labeled antibodies to histamine have shown that the unicellular Tetrahymena possess histamine binding sites (receptors) which are localized on the cilia of the cell body. No histamine is bound by the interciliar membrane regions and by the cilia of the oral fields.