NERVOUS FIBRES IN THE PARS INTERMEDIA OF THE TOAD BUFO ARENARUM

Abstract
Nerve fibers which enter from the neural lobe were found in the pars intermedia of the toad Bufo arenarum. Many of the mentioned fibers showed button-like endings between the cells located in the vicinity of capillaries. Degenerative changes were obtained in the axons of the pars intermedia of hypothalamus-transectioned animals. Neurosecretory substance appeared in close contact with the colloid-like vesicles of the pars intermedia cells. The neurosecretory droplets were always found near the intermediate-neural lobe junction. It is assumed that in Bufo arenarum there exists a morphological basis for admitting a direct axonal control from the hypothalamus to the pars intermedia.