Species-specific chemosignals evoke delayed excitation of the vomeronasal amygdala in freely-moving female rats.
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.
Mucignat-Caretta
Carla
C
Dipartimento di Anatomia e Fisiologia, Università degli Studi di Padova, Padova, Italy.
Colivicchi
Maria A
MA
Fattori
Manuela
M
Ballini
Chiara
C
Bianchi
Loria
L
Gabai
Gianfranco
G
Cavaggioni
Andrea
A
Della Corte
Laura
L
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
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