Catecholaminergic axons innervate LH-releasing hormone immunoreactive neurons of the human diencephalon.
Catecholamines have been shown to modulate gonadal functions via interactions with hypothalamic LH-releasing hormone (LHRH)-synthesizing neurons. To reveal the morphological background of this phenomenon, the distribution of LHRH neurons and tyrosine hydroxylase (TH)-immunoreactive (IR), catecholaminergic structures were mapped in the human diencephalon. First, the location of LHRH and TH-IR neuronal elements was analyzed, and then the relationship between the two different systems was examined. The LHRH-IR cell bodies were mainly present in the medial preoptic and infundibular areas. The TH-IR perikarya were located in the periventricular, paraventricular, and supraoptic hypothalamic nuclei and also in the median eminence. The TH-IR fibers were numerous in septal, infundibular, periventricular, and lateral hypothalamic regions. The brown, diaminobenzidine-labeled LHRH-containing perikarya were found to receive black, silver-intensified, TH-positive axon terminals in the infundibular and medial preoptic areas. However, in the preoptic and caudal parts of the diencephalon, only a few juxtapositions were noted. The present results indicate that hormone released from diencephalic LHRH-IR neurons in humans may be influenced by the central catecholaminergic system via direct synaptic mechanisms.
Dudás
B
B
Department of Pharmacology and Experimental Therapeutics, Loyola University Chicago, Strich School of Medicine, Maywood, Illinois 60153, USA.
Merchenthaler
I
I
D000328:Adult; D000368:Aged; D001369:Axons / Q000502:physiology*; D002395:Catecholamines / Q000502:physiology*; D004027:Diencephalon / Q000166:cytology / Q000502:physiology*; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000502:physiology*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D009474:Neurons / Q000502:physiology*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
D002395:Catecholamines; D007987:Gonadotropin-Releasing Hormone; D014446:Tyrosine 3-Monooxygenase