Biomedical subjects

Yuki Takayanagi

Publications and source records attributed to Yuki Takayanagi.

3 recordsLinked to original sources

PubMed2005

Pervasive social deficits, but normal parturition, in oxytocin receptor-deficient mice.

The oxytocin receptor (OXTR) and its ligand, oxytocin (OXT), regulate reproductive physiology (i.e., parturition and lactation) and sociosexual behaviors. To define the essential functions of OXTR, we generated mice with a null mutation in the Oxtr gene (Oxtr(-/-)) and compared them with OXT-deficient (Oxt(-/-)) mice. Oxtr(-/-) mice were viable and had no obvious deficits in fertility or reproductive behavior. Oxtr(-/-) dams exhibited normal parturition but demonstrated defects in lactation and maternal nurturing. Infant Oxtr(-/-) males emitted fewer ultrasonic vocalizations than wild-type littermates in response to social isolation. Adult Oxtr(-/-) males also showed deficits in social discrimination and elevated aggressive behavior. Ligand Oxt(-/-) males from Oxt(-/-) dams, but not from Oxt(+/-) dams, showed similar high levels of aggression. These data suggest a developmental role for the OXT/OXTR system in shaping adult aggressive behavior. Our studies demonstrate that OXTR plays a critical role in regulating several aspects of social behavior and may have important implications for developmental psychiatric disorders characterized by deficits in social behavior.

Aggression↗

PubMed2005

Salt loading reduces hypothalamic noradrenaline release after noxious stimuli.

Salt loading reduces neuroendocrine responses to stressful stimuli. Noxious stimuli facilitate noradrenaline release in the hypothalamus and, as a result, activate oxytocin neurones. Here, we examined effects of salt loading upon plasma oxytocin concentrations and noradrenaline release in the hypothalamus after footshocks. Male rats were allowed to drink 2% NaCl for 7 days. Salt loading reduced the footshock-induced increase in plasma oxytocin concentrations and noradrenaline release in the supraoptic nucleus (SON). Acute administration of hypertonic saline also attenuated the footshock-induced noradrenaline increase in the supraoptic nucleus. In contrast, salt loading did not significantly change activation of A1 catecholaminergic neurones in the medulla oblongata, as measured by expression of Fos protein. These data suggest that salt loading presynaptically suppresses noradrenaline release in the hypothalamus and oxytocin release into the blood after footshocks.

Administration, Oral↗

PubMed2003

Vasopressin-induced contraction of uterus is mediated solely by the oxytocin receptor in mice, but not in humans.

In the non-pregnant mouse myometrium, both arginine vasopressin and oxytocin induced contractions (pD(2)=8.55+/-0.13 and 9.23+/-0.09, respectively). The effect of oxytocin was the most potent, while the maximum contractions induced by these two peptides were almost of the same magnitude. Both vasopressin- and oxytocin-induced contractions were strongly inhibited by an oxytocin receptor antagonist, CL-12-42 (d(CH(2))(5)[Tyr(Me)(2),Thr(4),Tyr-NH(2)(9)]OVT), and weakly inhibited by a vasopressin V(1a) receptor antagonist, SR49059 ((2S)1-[(2R,3S)-5-chloro-3-(2-chlorophenyl)-1-(3,4-dimethoxybenzene-sulfonyl)-3-hydroxy-2,3-dihydro-1H-indole-2-carbonyl]-pyrrolidine-2-carboxamide). Similar results were obtained in the pregnant mouse myometrium. These results suggest that not only oxytocin- but also vasopressin-induced contraction is mediated by the activation of oxytocin receptors in the mouse myometrium. A reverse transcription polymerase chain reaction study failed to reveal mRNA of the vasopressin V(1a) receptor in the mouse myometrium. In contrast, in the non-pregnant human myometrium, vasopressin-induced contraction was inhibited by SR49059. Oxytocin showed no effect on the myometrium. These results suggest that there are significant differences in the functional receptors and contractile responses to vasopressin and oxytocin in the human and mouse uteri.

Adult↗