To examine the sex differences in the crowing behavior of the Japanese quail, we investigated the effects of sex steroids on calling behaviors using female birds, and the data were compared with those obtained in our ...To examine the sex differences in the crowing behavior of the Japanese quail, we investigated the effects of sex steroids on calling behaviors using female birds, and the data were compared with those obtained in our previous study in male birds which was performed using the same experimental procedures as those in the present study. We injected the female quails daily from 11 to 41 days after hatching with testosterone propionate (TP), 5α-dihydrotestosterone (DHT;a non-aromatizable androgen), estradiol benzoate (EB) or vehicle, and examined their calling behaviors in both sexual and non-sexual contexts. In a non-sexual context of the birds being isolated in a recording chamber, androgens, either TP or DHT, induced crowing in place of distress calling while EB simply inhibited distress calling. These effects of sex steroids on the calling behaviors were almost identical to those in the male quails. In a sexual context of the birds being left undisturbed in their home cages, crowing was induced by chronic treatment with TP, but not either DHT or EB, suggesting that both estrogenic and androgenic actions are required to induce the sexually motivated crowing. Although these results were basically the same as those in the male quails, the crowing in the female quails occurred much less frequently compared to that of the male quails. These data suggest that in the Japanese quail, crowing behavior, when it is restricted to sexually motivated one, is quantitatively different between male and female in the responsiveness to sex steroids.展开更多
Melatonin (MEL) has been reported to have acute enhancing effects on some aspects of cognition. Recently, we revealed that N1-acetyl-5-methoxyquinuramine (AMK), a brain metabolite of MEL, is much more potent than MEL ...Melatonin (MEL) has been reported to have acute enhancing effects on some aspects of cognition. Recently, we revealed that N1-acetyl-5-methoxyquinuramine (AMK), a brain metabolite of MEL, is much more potent than MEL in converting short-term memory (STM) to long-term memory (LTM) with a single administration immediately after the acquisition trial of the novel object recognition (NOR) task. These data suggest that the memory-enhancing effects of MEL may be mediated by mechanisms independent of the activation of MEL MT1 and MT2 receptors. In the present study, we examined the contribution of MT1 and MT2 receptor-mediated and non-receptor-mediated mechanisms to the acute memory-enhancing effects of MEL using NOR task. Mice were administered with either MEL, AMK, or a highly selective MT1/MT2 receptor agonist ramelteon (RAM) immediately after the acquisition trial and the effects of varying doses of these drugs on both STM and LTM performance were compared. We found that both AMK and RAM were more potent than MEL in both facilitating STM and promoting LTM formation. We also found that pretreatment with luzindole, a MT1/MT2 receptor antagonist, markedly suppressed only the effects of RAM. These results suggest that acutely administered MEL enhances NOR memory through both MT1 and MT2 receptor-mediated and non-receptor-mediated mechanisms.展开更多
文摘To examine the sex differences in the crowing behavior of the Japanese quail, we investigated the effects of sex steroids on calling behaviors using female birds, and the data were compared with those obtained in our previous study in male birds which was performed using the same experimental procedures as those in the present study. We injected the female quails daily from 11 to 41 days after hatching with testosterone propionate (TP), 5α-dihydrotestosterone (DHT;a non-aromatizable androgen), estradiol benzoate (EB) or vehicle, and examined their calling behaviors in both sexual and non-sexual contexts. In a non-sexual context of the birds being isolated in a recording chamber, androgens, either TP or DHT, induced crowing in place of distress calling while EB simply inhibited distress calling. These effects of sex steroids on the calling behaviors were almost identical to those in the male quails. In a sexual context of the birds being left undisturbed in their home cages, crowing was induced by chronic treatment with TP, but not either DHT or EB, suggesting that both estrogenic and androgenic actions are required to induce the sexually motivated crowing. Although these results were basically the same as those in the male quails, the crowing in the female quails occurred much less frequently compared to that of the male quails. These data suggest that in the Japanese quail, crowing behavior, when it is restricted to sexually motivated one, is quantitatively different between male and female in the responsiveness to sex steroids.
文摘Melatonin (MEL) has been reported to have acute enhancing effects on some aspects of cognition. Recently, we revealed that N1-acetyl-5-methoxyquinuramine (AMK), a brain metabolite of MEL, is much more potent than MEL in converting short-term memory (STM) to long-term memory (LTM) with a single administration immediately after the acquisition trial of the novel object recognition (NOR) task. These data suggest that the memory-enhancing effects of MEL may be mediated by mechanisms independent of the activation of MEL MT1 and MT2 receptors. In the present study, we examined the contribution of MT1 and MT2 receptor-mediated and non-receptor-mediated mechanisms to the acute memory-enhancing effects of MEL using NOR task. Mice were administered with either MEL, AMK, or a highly selective MT1/MT2 receptor agonist ramelteon (RAM) immediately after the acquisition trial and the effects of varying doses of these drugs on both STM and LTM performance were compared. We found that both AMK and RAM were more potent than MEL in both facilitating STM and promoting LTM formation. We also found that pretreatment with luzindole, a MT1/MT2 receptor antagonist, markedly suppressed only the effects of RAM. These results suggest that acutely administered MEL enhances NOR memory through both MT1 and MT2 receptor-mediated and non-receptor-mediated mechanisms.
