MULTIPLE SOURCES OF THE PITUITARY PARS-INTERMEDIA INNERVATION IN AMPHIBIANS - A DII RETROGRADE TRACT-TRACING STUDY

Afferent projections to the pituitary pars intermedia were studied usi ng the Dil tract-tracing technique in two amphibian species, the urode lan Triturus carnifex, and the anuran Rana esculenta. After Dil crysta l application into the pituitary intermediate lobe, in both species ce lls were retrogradely labeled in the preoptic nucleus, in the supra- a nd retro-chiasmatic hypothalamus and in the brainstem (especially in t he area indicated as locus coeruleus). The findings are discussed in r elation to data on the neurochemical nature of the innervation of the pars intermedia in amphibians.