Associate Professor
Phillips Hall 341
hamster ova
Education
- Ph.D. University of Oregon
- M.S. University of Wisconsin - Milwaukee
- B.S. University of Wisconsin - Madison
Courses
- Biol 211 Organismal Form and Function
- Biol 317 Animal Physiology
- Biol 470 Neurobiology
Research - Neurobiology
We work on problems related to circadian rhythms - how the brain and hormones control them and how circadian rhythms, in turn, influence hormones and behavior. In particular, we are interested in how the circadian clock is reset by stimuli other than light, that is, nonphotic stimuli. What are the neural pathways involved in clock resetting? Which neurotransmitters mediate the response? What role do nonphotic stimuli play in the synchronization of daily rhythms to environmental cycles?
- Adrenergic Mediation of Clock Resetting
- Clock Resetting Effects on Female Reproduction
- Selected Publications:
Young Janik, L.. and D. Janik. 2003. Nonphotic Phase Shifting in Female Syrian Hamsters: Interactions with the Estrous Cycle. Journal of Biological Rhythms 18: 307-317.
Janik, D., Nest, K.J. and Janiga, M.A. 2001. Exogenous corticosteroid and shifts of circadian rhythms in hamsters. Chronobiology International 18: 173-186.
Andy taking a break from data analysis and Carly preparing solutions
We have found that the beta-adrenergic antagonist, propranolol greatly reduces the magnitude of clock resetting. We are currently trying to determine what types of beta receptors mediate this response and whether resetting can be stimulated by adrenergic agonists.
A nonphotic phase shift Propranolol reduces nonphotic phase shifts
Hamsters have a very predictable four-day estrous cycle. However, when the circadian clock of a female hamster is reset on the day before she normally ovulates, her estrus cycle is delayed by one day. We are currently examining the physiology of this response by measuring ovulation and levels of the hormone LH.
