Effect of periodic social interaction and odour presentation of same and opposite-sex conspecifics on free-running mice

ABSTRACT

Social interaction, a non-photic cue, plays a role in the synchronization of circadian rhythm under constant environmental conditions. However, little is known about the effect of sex-specific interaction and sex-specific odor on the free-running circadian clock of mice. Hence, in the present study, we investigated the effect of social interaction and odor presentation of same and opposite-sex conspecifics on the free-running rhythm of mice. In this investigation, stranger and dummy mice (saturated with either male- or female-associated odor) were separately exposed to the same and opposite-sex conspecifics of male and female runners and receivers, respectively for 30 min at CT15 for 10–12 d. The results showed that the daily exposure of runners with same and opposite-sex strangers entrained the free-running locomotor activity rhythm in a gender-specific manner. However, daily exposure of same and opposite-sex conspecific odors masked the circadian rhythm of receiver animals by increasing the activity. Further, social interaction and odor presentation caused lengthened and shortened period length, respectively. These results suggest that periodic social interactions can produce entrainment and conspecific odor can produce only masking on free-running circadian locomotor activity rhythm in mice.

KEYWORDS:

• Circadian rhythm
• free-running rhythm
• olfactory cue
• social interaction
• masking

Acknowledgements

UGC-RGNF JRF & SRF Fellowship to PS [Award No. F117.1/201516/ RGNF201517SCUTT4822/(SAIII/Website)] and Departmental facilities of UGC-CAS & DST-FIST, and ISLS, BHU are acknowledged. Dr. P. Basu and Dr. D. Kumar are gratefully acknowledged for critically reading the manuscript and providing language help.

Disclosure statement

We declare that no conflict of interests.

Ethical committee permission

Ethical approval was obtained from the Institutional Animal Ethical Committee of the Banaras Hindu University (BHU/DOZ/IAEC/2018-2019/026).

Additional information

Funding

UGC, New Delhi (No.6-2/2017/IC) to MS;University Grants Commission [No.6-2/2017/IC].