Gender difference in circadian clock responses for social interaction with conspecific of the opposite-sex

ABSTRACT

Social cues are potent non-photic modulators of the circadian clock and play a vital role in resetting the endogenous clock. Several lines of evidence strongly suggest a functional link between olfactory cues and the circadian clock. However, there is a paucity of information on the effects of social interaction with the conspecifics of the opposite sex on the circadian clock. Hence, we studied the effect of social cues of sexually mature naïve opposite sex of the conspecific on the phase resetting of the circadian clock at various circadian times (CT) and molecular changes at the suprachiasmatic nuclei (SCN) and odor responsive structure in the brain of mice. Sexually naïve adult male and female free-running mice (designated as ‘runners’) were exposed to the conspecifics of the opposite-sex (‘strangers’) for 30 min at CT3, CT9, CT15, and CT21. Both male and female ‘runners’ exhibited a phase advance at CT3, delay at CT21, and no response at CT9. However, at CT15 only the male ‘runners’ exhibited phase advance but not the female ‘runners’. Control mice did not elicit any significant phase shifts at all CTs. Social interactions with conspecifics of the opposite-sex up-regulated c-fos/C-FOS, omp in the olfactory bulb, per-1/PER-1 in the SCN, C-FOS, and PER-1 in the piriform cortex of both male and female runners at CT3. However, at CT15 up-regulation of variables only occurred in male but not in female runners. Together, the present investigation has shown the gender difference in circadian clock responses for social cues with conspecific of the opposite-sex in mice.

KEYWORDS:

• Circadian rhythm
• gender-specific differences
• olfactory cue
• phase shift
• phase response curve
• social interaction

Acknowledgements

Financial support by DST (SR/CSI/157/2012), UGC-ISF (No.6-2/2017/IC) to MS is gratefully acknowledged. UGC-RGNF JRF & SRF Fellowship grant to PS and Departmental facilities of UGC-CAS & DST-FIST, and ISLS, BHU are acknowledged. Dr. P. Basu is gratefully acknowledged for critically reading the manuscript and providing language help.

Disclosure statement

The authors declare no conflict of interest.

Ethical ion

The Institutional Animal Ethical Committee of the Banaras Hindu University approved the experimental protocols (BHU/DOZ/IAEC/2018-2019/026).

Additional information

Funding

This work was supported by the Department of Science and Technology, New Delhi [SR/CSI/157/2012]; University Grants Commission, New Delhi [No.6-2/2017/IC].