title: Changes in formaldehyde-induced fluorescence of the hypothalamus and pars intermedia in the frog, Rana temporaria, following background adaptation.
abstract: Adaptation of the frog, Rana temporaria, to a white background for 12 hr has resulted in an intense formaldehyde-induced fluorescence (FIF) in the neurons of the preoptic recess organ (PRO), paraventricular organ (PVO), nucleus infundibularis dorsalis (NID) and their basal processes permitting visualization of the PRO- and PVO-hypophysial tracts that extend into the median eminence (ME) and pars intermedia (PI); the FIF is reduced in all the structures by 3 days. In frogs adapted to a black background, for 12 hr and 3 days, there was a general reduction in the FIF of the PRO neurons and PRO-hypophysial tract. By 12 hr black background adaptation, the PVO/NID neurons and only their adjacent basal processes show FIF which was sharply reduced by 3 days, making the PVO-hypophysial tract undetectable. In the PI fibers the fluorescence was more intense in black-adapted frogs than in white-adapted ones at both the intervals studied. The simultaneous changes in the FIF of the hypothalamic nuclei, tracts and PI suggest that the PRO and PVO/NID neurons participate in PI control through release of neurotransmitter(s) at the axonal ends.
mesh_terms: D000818:Animals; D001369:Axons / Q000648:ultrastructure; D002395:Catecholamines / Q000378:metabolism*; D005557:Formaldehyde; D007031:Hypothalamus / Q000033:anatomy & histology*; D008473:Median Eminence / Q000033:anatomy & histology; D008856:Microscopy, Fluorescence / Q000379:methods*; D009433:Neural Inhibition; D010286:Paraventricular Hypothalamic Nucleus / Q000033:anatomy & histology; D010902:Pituitary Gland / Q000033:anatomy & histology*; D011301:Preoptic Area / Q000033:anatomy & histology; D011896:Rana temporaria
chemical_list: D002395:Catecholamines; D005557:Formaldehyde