The University of Osaka · Neuroscience
Professor Masaharu Hasebe's research lab focuses on the neuroendocrine mechanisms underlying seasonal adaptation in animals, with a particular emphasis on photoperiodic regulation of reproduction. The lab investigates how circadian clock genes and neuronal signaling—especially glutamate dynamics and kisspeptin neurons—integrate environmental light cues to control reproductive physiology. Using model organisms such as the bean bug *Riptortus pedestris* and medaka, the lab combines neurogenetics, electrophysiology, and in vivo imaging to dissect the cellular and systemic basis of seasonal breeding. A central theme is understanding the interaction between metabolic status, neural circuits, and reproductive function across species and sexes.
Figures are computed from collected data and may differ slightly.
Animals show photoperiodic responses in physiology and behavior to adapt to seasonal changes. Recent genetic analyses have demonstrated the significance of circadian clock genes in these responses. However, the importance of clock genes in photoperiodic responses at the cellular level and the physiological roles of the cellular responses are poorly understood. The bean bug <i>Riptortus pedestris</i> shows a clear photoperiodic response in its reproduction. In the bug, the pars intercerebralis (P
Animals adequately modulate their physiological status and behavior according to the season. Many animals sense photoperiod for seasonal adaptation, and the circadian clock is suggested to play an essential role in photoperiodic time measurement. However, circadian clock-driven neural signals in the brain that convey photoperiodic information remain unclear. Here, we focused on brain extracellular dynamics of a classical neurotransmitter glutamate, which is widely used for brain neurotransmissio
Close interaction exists between energy-consuming reproduction and nutritional status. However, there are differences in costs and priority for reproduction among species and even between sexes, which leads to diversification of interactions between reproduction and nutritional status. Despite such diversified interactions among species and sexes, most of the analysis of the nutritional status-dependent regulation of reproduction has been limited to an endothermic vertebrate, mammalian species o
Enterally delivered GLU may be a preferable fuel for the enterocytes and enhance the mucosal protein synthesis. GLU probably can substitute for GLN in supplementation to an enteral diet regarding many roles GLN plays in the intestinal mucosa under stress situations.
Kisspeptin (Kiss) neurons show drastic changes in kisspeptin expression in response to the serum sex steroid concentration in various vertebrate species. Thus, according to the reproductive states, kisspeptin neurons are suggested to modulate various neuronal activities, including the regulation of GnRH neurons in mammals. However, despite their reproductive state-dependent regulation, there is no physiological analysis of kisspeptin neurons in seasonal breeders. Here we generated the first kiss
Hypothalamic gonadotropin-releasing hormone (GnRH) neurons play an important role in promoting secretion of pituitary luteinizing hormone (LH) and ovulation by releasing GnRH peptide. The release of GnRH peptide is generally assumed to be mainly modulated according to the firing activity of GnRH neurons. However, the relationship between the firing activity and the release of GnRH peptide has been elusive. We analyzed the relationship using two lines of transgenic medaka (gnrh1:enhanced green fl
Many insects in temperate regions avoid environmental adversity for reproduction, and thus enter reproductive diapause according to photoperiod. This reproductive diapause is induced by inhibition of juvenile hormone biosynthesis in the corpus allatum. Some neuropeptides that have an effect on juvenile hormone biosynthesis have been detected in insect brains. Thus, the reproductive diapause may be photoperiodically regulated by these juvenile hormones-controlling neuropeptides. However, there is
The interneurons of the mushroom body, known as Kenyon cells, are essential for the long-term memory of olfactory associative learning in some insects. Some studies have reported that nitric oxide (NO) is strongly related to this long-term memory in Kenyon cells. However, the target molecules and upstream and downstream NO signaling cascades are not completely understood. Here we analyzed the effect of the NO signaling cascade on Na(+)-activated K(+) (KNa) channel activity in Kenyon cells of cri
Nutritional management often fails in critically ill patients such as trauma and sepsis because of their acutely progressive malnutrition and metabolic derangement being characteristic of such clinical settings. Nutritional strategies for these patients have been almost established by the methods of clinical epidemiology. A considerable amount of clinical evidences suggests that the following should be of benefit for the patients, enteral delivery of nutrition, a nutrition assessment including m
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