title: Species-specific chemosignals evoke delayed excitation of the vomeronasal amygdala in freely-moving female rats.
abstract: Male rat chemosignals attract females and influence their reproductive status. Through the accessory olfactory bulb and its projection target, the posteromedial cortical nucleus of the amygdala (PMCo), species-specific chemosignals detected by the vomeronasal organ (VNO) may reach the hypothalamus. To test this hypothesis in vivo, behavioural activation and neurotransmitter release in the PMCo were simultaneously monitored in freely moving female oestrus rats exposed to either rat or mouse urinary stimuli, or to odorants. Plasma levels of the luteinizing hormone were subsequently monitored. All stimuli induced an immediate behavioural activation, but only species-specific chemosignals led to a delayed behavioural activation. This biphasic behavioural activation was accompanied by a VNO-mediated release of the excitatory amino acids, aspartate and glutamate, in the PMCo. The late behavioural and neurochemical activation was followed by an increase in the levels of circulating luteinizing hormone. In conclusion, these data show that only species-specific chemosignals induce a delayed behavioural activation and excitatory activation of the PMCo, which is dependent on an intact VNO.
authors.affiliation: Dipartimento di Anatomia e Fisiologia, Università degli Studi di Padova, Padova, Italy.
authors.forename: Carla
authors.initials: C
authors.lastname: Mucignat-Caretta
authors.forename: Maria A
authors.initials: MA
authors.lastname: Colivicchi
authors.forename: Manuela
authors.initials: M
authors.lastname: Fattori
authors.forename: Chiara
authors.initials: C
authors.lastname: Ballini
authors.forename: Loria
authors.initials: L
authors.lastname: Bianchi
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Gabai
authors.forename: Andrea
authors.initials: A
authors.lastname: Cavaggioni
authors.forename: Laura
authors.initials: L
authors.lastname: Della Corte
mesh_terms: D000679:Amygdala / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism; D001522:Behavior, Animal / Q000502:physiology; D002628:Chemoreceptor Cells / Q000502:physiology*; D030762:Estrous Cycle / Q000502:physiology; D005260:Female; D005916:Globulins / Q000652:urine; D018698:Glutamic Acid / Q000378:metabolism; D006728:Hormones / Q000378:metabolism; D007986:Luteinizing Hormone / Q000097:blood; D017551:Microdialysis; D018377:Neurotransmitter Agents / Q000378:metabolism; D011374:Progesterone / Q000097:blood; D011507:Proteinuria / Q000652:urine; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000502:physiology*; D012903:Smell / Q000502:physiology; D026941:Sodium Channel Blockers / Q000494:pharmacology; D013268:Stimulation, Chemical; D013654:Taurine / Q000378:metabolism; D013779:Tetrodotoxin / Q000494:pharmacology; D014556:Urine / Q000737:chemistry; D019147:Vomeronasal Organ / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D005916:Globulins; D006728:Hormones; D018377:Neurotransmitter Agents; D026941:Sodium Channel Blockers; D013654:Taurine; D001224:Aspartic Acid; D018698:Glutamic Acid; D013779:Tetrodotoxin; D011374:Progesterone; D005680:gamma-Aminobutyric Acid; D007986:Luteinizing Hormone