Morphometrical and neurochemical changes in the anteroventral subdivision of the rat medial amygdala during estrous cycle

• Published in: Brain research Vol. 1150; pp. 83 - 93
• Main Authors: Carrillo, Beatriz, Pinos, Helena, Guillamón, Antonio, Panzica, GianCarlo, Collado, Paloma
• Format: Journal Article
• Language: English
• Published: London Elsevier B.V 30-05-2007; Amsterdam Elsevier; New York, NY
• Subjects: Amygdala - cytology; Amygdala - metabolism; Anatomy; Animals; Anteroventral subdivision of the medial amygdala; Biological and medical sciences; Brain Chemistry - physiology; Bromodeoxyuridine - metabolism; Cell Count; Central nervous system; Estrous Cycle; Female; Fundamental and applied biological sciences. Psychology; Glial Fibrillary Acidic Protein - metabolism; Male; NADPH Dehydrogenase - metabolism; Neurology; Neurons - metabolism; Nicotinamide adenine dinucleotide phosphate-diaphorase; Nitric oxide synthase; Nitric Oxide Synthase Type I - metabolism; Rat; Rats; Rats, Wistar; Sex Characteristics; Sexual diergism; Sexual dimorphism; Vertebrates: nervous system and sense organs; Sexual diergism; Rat; Anteroventral subdivision of the medial amygdala; Nicotinamide adenine dinucleotide phosphate-diaphorase; Nitric oxide synthase; Sexual dimorphism; Estrous cycle; Amygdala; Central nervous system; B-Vitamins; Encephalon; Amygdaloid nucleus; Dihydrolipoamide dehydrogenase; Enzyme; Rodentia; Adenine; Basal ganglion; Nitric-oxide synthase; Vertebrata; Mammalia; dinucleotide phosphate-diaphorase; Animal; Nicotinamide adenine; Nicotinamide; Oxidoreductases; Morphometry
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/j.brainres.2007.02.073

Abstract The anteroventral subdivision of the medial amygdala (MeAV) is one of the vomeronasal structures involved in the control of hormonally dependent behaviors such as sexual and agonistic behaviors in rats. The present study investigates some anatomical and neurochemical parameters of this nucleus (volume, number of neurons, number of glial elements, and of NADPH-diaphorase-positive neurons) in females in two estrous cycle phases (diestrous and estrous) and in males. We also investigate the possible existence of adult neurogenesis in this nucleus in the females. Results showed that volume and estimated number of Nissl-stained neurons in the MeAV vary with the estrous cycle phase: estrous females have greater values than diestrous females. As a consequence of these variations, there is a transient sex difference between males and diestrous females. Two subpopulations of NADPH-diaphorase-positive neurons were detected: intensely stained and medium stained. The intensely stained neurons were more numerous in the estrous than the diestrous females. Neither BrdU nor GFAP inmunostaining revealed significant differences between the two groups, suggesting that adult cell generation, i.e., increases in the number of glial elements, has no significant role in the changes detected in the number of Nissl-stained sections. In conclusion, the MeAV shows functional diergism, due to plastic changes in the female rat brain probably linked to the increase of estradiol during estrous. Finally, these changes are probably functionally related to changes in the behaviors that are controlled through this nucleus.