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These GnRH neurons and their projections to the median eminence
represent the final common pathway in the neural control of reproduction for
all vertebrates. To ensure that young are born at favorable times, temperate
zone species have adapted a highly successful strategy of restricting
reproductive activity to limited times of the year. Changes in daylength
serves as the predominant factor responsible for causing seasonal reproductive
transitions; hence, the resulting seasonality is considered 'Nature's
contraceptive'. Yet, how the daylength signal is conveyed to the GnRH neurons
remains a key unanswered question in the field of reproductive
neuroendocrinology. By using a combination of neuroanatomical, molecular, and
systems approaches, our goal is to advance a more unified hypothesis of the
neural mechanisms underlying the seasonal control of reproduction. Because
many mammals, including humans, exhibit daily and seasonal rhythms in behavior
and endocrine function, we are also very interested in understanding the
‘clock’ mechanisms that underlie these rhythms. To this end, projects are
designed to identify mechanisms involved in the generation of long-term
(yearly) reproductive rhythms. Other projects are examining the relationship
between daily rhythms and drug addiction relapse.
Biographical Information
Heiko T. Jansen, Associate Professor in VCAPP, received his B.A. in Biology
from Franklin Pierce College, Rindge, NH. He received both his M.S. in
Pharmacology/Toxicology (1987) and Ph.D. in Physiology (1993) from the
University of Illinois at Urbana/Champaign, IL. From 1993-1997 he did
postdoctoral work at the University of Cincinnati and was awarded an NIH
post-doctoral fellowship. In 1997, he was appointed to the faculty at the
University of Cincinnati as Research Assistant Professor and also served as
a member of the Neuroscience Graduate Program. From 1997-1999, he also
served as an adjunct faculty member in the Biology Department of Xavier
University. He joined the Department of VCAPP at Washington State University
and the Neuroscience Graduate Faculty in the summer of 2000.
Recent Publications
Jansen HT, Hildeman
SM, Lubbers LS, Kuehl DE, Jackson GL, and Lehman MN. Identification and
distribution of neuroendocrine GnRH neurons in the ewe. Biol.
Reprod. 56: 655-662, 1997.
Lehman, MN, Goodman RL, Karsch FJ, Jackson GL, Berriman SJ, and Jansen HT. The
GnRH system of seasonal breeders: anatomy and plasticity. Proceedings of the
5th International Conference on Hormones,
Brain, and Behavior. Brain Res. Bull. 44(4):
445-457, 1997.
Jansen HT, Iwamoto GA, and Jackson GL. Central connections of the ovine
olfactory bulb formation identified using wheat germ agglutinin-conjugated
horseradish peroxidase. Brain Res. Bull 45(1):
27-39, 1997.
Silver R, Sookhool AL, LeSauter J;, Stevens P, Jansen HT, and Lehman MN.
Multiple regulatory elements result in regional specificity in circadian
rhythms of neuropeptide expression in mouse SCN. NeuroReport
10: 3165-3174, 1999.
Coolen LM, Jansen HT, Goodman RL, Wood RI, and Lehman MN. A method for
simultaneous demonstration of anterograde and retrograde connections in the
brain: co-injections of biotinylated dextran amine and the beta subunit of
cholera toxin. J. Neurosci. Meth. 91: 1-8, 1999.
Jansen HT, West C, Lehman MN, and Padmanabhan V. Changes in ovarian estrogen
receptor-b mRNA expression prior to ovulation
in the ewe. Biol. Reprod. 65: 866-872, 2001.
Jansen HT, Cutter C, Hardy S, Lehman MN, and Goodman RL. Seasonal plasticity
within the GnRH system of the ewe: changes in identical GnRH inputs and in
glial association. Endocrinology 144:
3663-3676, 2003.
Sleipness EP, Sorg BA, and Jansen HT. Time of day alters long-term
sensitization to cocaine in rats. Brain Res. 1065:
132-137, 2005.
Jansen HT, Kirby JD, Cooke PS, Arambepola N, Iwamoto GA. Impact of neonatal
hypothyroidism on reproduction in the male hamster, Mesocricetus auratus.
Physiol Behav. 90: 771-781, 2007.
Sleipness E, Sorg BA, and Jansen HT. Diurnal differences in dopamine
transporter and tyrosine hydroxylase leves in the rat brain: dependence on
the suprachiasmatic nucleus. Brain Res. 1129:
34-42, 2007
Sleipness E, Sorg BA, and Jansen HT. Contribution of the suprachiasmatic
nucleus to cocaine-seeking behavior. Physiol. Behav.
2007 (in press).
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