Neurochemistry and Plasticity of the Median Eminence and Neural Pituitary Lobe in Relation to Background Adaptation of Xenopus laevis

Abstract

Using immunocytochemistry and morphometry we have supported our hypothesis that magnocellular neurons in the preoptic area of the brain of Xenopus laevis release identical sets of neuropeptides containing not only the previously identified vasotocin, mesotocin, corticotropin-releasing factor, thyrotropin-releasing hormone, brain-derived neurotrophic factor, urocortin 1, and pituitary adenylate cyclase-activating peptide but also mesotocin and met-enkephalin from both neurohemal areas in the pituitary neural lobe and in the median eminence. We also show that the external zone of the median eminence is plastic, depending in size on the state of background illumination.