Appositions between cocaine and amphetamine-related transcript- and gonadotropin releasing hormone-immunoreactive neurons in the hypothalamus of the Siberian hamster.
Recent in vitro studies have provided evidence that cocaine and amphetamine-related transcript (CART) pathways in the hypothalamus mediate the effects of leptin upon gonadotropin releasing hormone (GnRH) secretion. The aim of the current study was to use dual label immunofluorescence to investigate the anatomical basis of such a pathway. CART-ir processes were found extensively in regions where GnRH cell bodies where located. Analysis using confocal microscopy showed that the majority of GnRH neurons (62%) had close appositions from CART-ir processes. The proportion of GnRH-ir perikarya with CART-ir appositions was significantly higher (P<0.05) in neurons located in the diagonal band of Broca (70%) compared to those more caudally located in the preoptic area (53%). This anatomical evidence for close appositions between CART-ir processes and GnRH cell bodies supports the hypothesis that one mechanism by which leptin causes its effect on the GnRH pulse generator is indirectly via CART neurons, thus allowing information about nutritional status and body fat stores to be conveyed to the reproductive system.
Leslie
R A
RA
School of Biomedical Sciences, University of Nottingham Medical School, Queens Medical Centre, Nottingham, NG7 2UH, UK.
Sanders
S J
SJ
Anderson
S I
SI
Schuhler
S
S
Horan
T L
TL
Ebling
F J
FJ
D000818:Animals; D002450:Cell Communication / Q000502:physiology; D006224:Cricetinae; D004734:Energy Metabolism / Q000502:physiology; D005260:Female; D012739:Gonadal Steroid Hormones / Q000378:metabolism; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007031:Hypothalamus / Q000166:cytology / Q000378:metabolism*; D007150:Immunohistochemistry; D020738:Leptin / Q000378:metabolism*; D018613:Microscopy, Confocal; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009434:Neural Pathways / Q000378:metabolism* / Q000648:ultrastructure; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D017111:Phodopus; D011301:Preoptic Area / Q000166:cytology / Q000378:metabolism; D017729:Presynaptic Terminals / Q000378:metabolism / Q000648:ultrastructure; D012686:Septal Nuclei / Q000166:cytology / Q000378:metabolism; D013569:Synapses / Q000378:metabolism* / Q000648:ultrastructure; D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein
D012739:Gonadal Steroid Hormones; D020738:Leptin; D009419:Nerve Tissue Proteins; D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein; D007987:Gonadotropin-Releasing Hormone