Biology subjects

Kagawa, K.

Publications and source records attributed to Kagawa, K..

3 recordsLinked to original sources

bioRxiv2026

Male odor preference in female mice is modulated across reproductive stages via the posteroventral medial amygdala.

Male odor induces various behavioral and physiological responses across the reproductive cycle in female mice. Although male odor preference in females is reduced during pregnancy, how it changes across later stages of the reproductive cycle, including nursing and weaning, remains unclear. Here, we found that male odor preference is lost during pregnancy and nursing. To identify the olfactory systems involved in these changes, we examined neural activity using c-Fos immunohistochemistry. Male odor exposure during nursing increased neural activity in the accessory olfactory bulb and the posteroventral medial amygdala (MeApv), a key node of the accessory olfactory system, as well as in subdivisions of the central amygdala, but not in the ventromedial hypothalamus or the bed nucleus of the stria terminalis. Finally, lesions of the MeApv prevented the loss of male preference during nursing, indicating that the MeApv is required for suppression of male preference during this stage.

neuroscience↗

bioRxiv2025

Morning sickness-like changes during pregnancy in non-human primates and rodents

Nausea and vomiting of pregnancy (NVP), commonly referred to as "morning sickness," causes a range of symptoms including nausea, vomiting, weight loss, anorexia, and malaise in pregnant women during early pregnancy. Although NVP highly affects the quality of life of pregnant women, the absence of model animals has prevented us from revealing the underlying mechanisms. Here, to identify whether non-human animals may serve as models for studying NVP, we analyzed metabolic changes during pregnancy in common marmosets and mice. Marmosets exhibited a transient weight decrease during the period of placental development in approximately 22% of pregnancies. Some marmosets repeatedly showed transient weight loss across multiple pregnancies, suggesting individual variations in the likelihood of NVP-like symptoms. Although mice did not show apparent alteration in body weight, they exhibited a slowdown in food intake and alterations in locomotor activity during the corresponding phase. These shared alterations suggest that marmosets and mice may exhibit phenomena analogous to human NVP and could serve as useful models for investigating its biological basis. HighlightsO_LIMarmosets exhibited a transient weight loss during placental development in 22% of pregnancies. C_LIO_LIThere was individual variation in how often the transient weight loss occurred in marmosets. C_LIO_LIFood intake and activity in C57BL/6 mice are altered during the corresponding gestational phase. C_LIO_LIMultiple morning sickness-like phenomena were observed in non-human mammals. C_LI

physiology↗

bioRxiv2025

The interplay of sexual selection and hybridization can drive sexual radiation

Sexual selection is considered a major driver of species diversification, but little is known about whether and how sexual selection may contribute to the incipient stages of speciation and sexual radiation. Based on evolutionary simulations, here I propose that an interplay of sexual selection and hybridization can drive the rapid formation of multiple species with diverse exaggerated sexual displays within a lineage. Existing theories suggest that sexual selection can cause evolutionary dynamics with multiple stable equilibria, with which multiple species with distinct sexual displays and mate preferences can persist stably. However, the stability of each equilibrium hinders the formation of new species from an existing species that is already occupying one of the stable equilibria. In such situations, hybridization between phenotypically similar but genetically distinct lineages can catalyze speciation. Hybridization can generate genetic variation by recombining alleles from different lineages. I provide evolutionary simulations demonstrating that hybridization that gives rise to genetic variation in mate preference can modify the sexual selection regime to open up opportunities for the evolution of sexually selected displays toward previously unoccupied stable equilibria. Hybridization thus can trigger evolutionary shifts between alternative evolutionary equilibria that sexual selection generates, driving the incipient formation of sexual radiation.

evolutionary biology↗