Distribution of somatostatin in the frog brain, Rana catesbiana, in relation to location of catecholamine-containing neuron system.

The distribution of somatostatin (SRIF)-immunoreactive structures in the central nervous system of the bull frog (both with and without treatment of colchicine) was studied, using the indirect immunofluorescence technique of Coons and co-workers (Coons, '58). SRIF-containing cells were observed in more than ten areas including the spinal cord. These SRIF-positive cells showed segmental distribution, in that SRIF-positive neurons were identified in various areas at various brain levels. An extensive network of SRIF-positive fibers was found in most parts of the central nervous system. The distribution of a catecholamine (CA)-containing neuron system in the frog brain is also presented in this study. The possible interactions between SRIF and CA neurons systems are briefly discussed.