Washington University in St. Louis
Campus Box 1037
One Brookings Drive
St. Louis, MO 63130-4899
Biological clocks that drive near 24-hour rhythms in behavior and physiology have been found in a wide variety of organisms and cell types. The Herzog Lab studies the cellular and molecular basis of these circadian rhythms in mammals using techniques that include planar electrode arrays, cellular imaging and genetic manipulations (i.e. mutants, knockouts, and transgenics). This approach is producing insight into the roles of specific molecules, cells, and tissues in the rich repertoire of daily behaviors. In mammals, the suprachiasmatic nucleus (SCN) of the hypothalmus is the master circadian pacemaker. This brain region continues to keep daily time when cultured. We are now asking which cells generate this rhymicity, how do they synchronize to one another, and what makes them unique in their ability to keep time?
Photo caption: Neurons from the suprachiasmatic nucleus (SCN) express near 24-hour ("circadian") rhythms in electrical activity in culture. Firing rate rises during the day and falls at night for these two SCN cells despite being maintained in vitro without any temporal cues.
GABA networks destabilize genetic oscillations in the circadian pacemaker. Freeman GM Jr, Krock RM, Aton SJ, Thaben P, Herzog ED. Neuron. 2013 Jun 5;78(5):799-806
Freeman GM Jr, Nakajima M, Ueda HR, Herzog ED. J Neurophysiol. 2013 Jul;110(1):103-8.
Weakly circadian cells improve resynchrony. Webb AB, Taylor SR, Thoroughman KA, Doyle FJ 3rd, Herzog ED. PLoS Comput Biol. 2012;8(11):e1002787.
I(A) channels encoded by Kv1.4 and Kv4.2 regulate neuronal firing in the suprachiasmatic nucleus and circadian rhythms in locomotor activity. Granados-Fuentes D, Norris AJ, Carrasquillo Y, Nerbonne JM, Herzog ED. J Neurosci. 2012 Jul 18;32(29):10045-52.
Spatiotemporal distribution of vasoactive intestinal polypeptide receptor 2 in mouse suprachiasmatic nucleus. An S, Tsai C, Ronecker J, Bayly A, Herzog ED. J Comp Neurol. 2012 Aug 15;520(12):2730-41.
Freeman GM Jr, Herzog ED (2011) Neuropeptides go the distance for circadian synchrony. Proc Natl Acad Sci U S A. 108:13883-4.
Marpegan L, Swanstrom AE, Chung K, Simon T, Haydon PG, Khan SK, Liu AC, Herzog ED, Beaulé C (2011) Circadian regulation of ATP release in astrocytes. J Neurosci. 31:8342-50.
An S, Irwin RP, Allen CN, Tsai C, Herzog ED (2011) Vasoactive intestinal polypeptide requires parallel changes in adenylate cyclase and phospholipase C to entrain circadian rhythms to a predictable phase. J Neurophysiol. 2011 May;105(5):2289-96.
Webb AB, Angelo N, Huettner JE, Herzog ED (2009) Intrinsic, nondeterministic circadian rhythm generation in identified mammalian neurons. Proc Natl Acad Sci U S A. 2009 Sep 22;106(38):16493-8.
Marpegan L, Krall TJ, Herzog ED (2009) Vasoactive intestinal polypeptide entrains circadian rhythms in astrocytes. J Biol Rhythms. 24:135-43.
Herzog ED (2007) Neurons and networks in daily rhythms. Nat Rev Neurosci. 8:790-802.