Tachykinin immunoreactivity in the European common frog, Rana temporaria: localization, quantification and chromatographic characterization.

1. Tachykinin immunoreactivity has been localized, quantified and chromatographically-characterized in the brain, stomach, intestine and skin of Rana temporaria. 2. Antisera to mammalian substance P (SP) and neurokinin A (NKA) immunostained nerve fibres in all tissues except skin, and a population of mucosal endocrine cells in the intestinal epithelium. 3. Radioimmunoassay of tissue extracts identified SP immunoreactivity in all tissues but NKA immunoreactivity was restricted to the brain. 4. Chromatographic analysis of both frog tachykinins revealed that they possessed different physico-chemical properties than their mammalian counterparts.