Dr. Gerard Heck
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Contact Information
Department of Physiology and Biophysics Virginia Commonwealth University P.O. Box 980551 Richmond, Virginia 23298-0551 Tel: 804-828-1850 Fax: 804-828-7382 email: gheck@vcu.edu |
Dr Heck received his B.S. in Biology at Notre Dame in 1967. His Ph.D. was conferred at Duke University in 1974 after study in the laboratory of Dr. Robert Erickson. He joined VCU in 1978 as a postdoctoral fellow and joined the faculty in 1980.
Research
Knowledge of the mechanisms involved in taste transduction is useful not only for understanding of disease states but also for activities of everyday life. The award of the 2004 Nobel Prize in Physiology to chemoreception researchers in olfaction emphasizes the importance and impact of the discovery of the underlying molecular mechanisms. My work specializes in the study of the transduction of ionic taste stimuli. We have developed a number of techniques which allow us to investigate the involvement of receptors and/or ion channels in the intact animal preparation. Others in our group use optical methods to measure actual ion fluxes in polarized taste buds. We are currently involved in identifying non-specific channels contributing to salt taste and proton channels which contribute to the sour taste.
A number of studies on taste receptors have used the response recorded from tongue nerves as an assay for the phenotype of gene-modified mice. The lab uses this same chemically-evoked taste response in the rodent chorda tympani nerve as a relevant proxy for taste sensation. We expand upon it, however, by using techniques from epithelial physiology in the stimulation process; we can voltage- or current-clamp a well-defined receptive field of the tongue surface. This is particularly useful for the study of taste transduction mechanisms which may depend upon ion channels such as salty or acid taste. Our previous studies used these techniques to establish the involvement of the epithelial amiloride-sensitive sodium channel in rodent taste. The voltage-clamp technique reveals that anion inhibition of the taste response is a property of the polarized epithelium and depends on the selectivity of the epithelial tight junctions.
Until some of our recent studies, the in-vivo, evoked chorda tympani response in rodents had seemed resistant to modification with pharmacologic probes with basolateral or intracellular targets. Judicious use of adjuvants to bypass tight-junction barriers has allowed us to develop pharmacologic dissection techniques; we now employ a wide array of channel blockers and intracellular modulators. One of our recent studies demonstrated the equivalence of the neural response in a pharmacologically-blocked control mouse when contrasted with the response in a Trpv1 knockout mouse.
Selected Publications
Heck, G.L. and Erickson, R.P.: A rate theory of gustatory stimulation. Behavioral Biology 8: 687-712, 1973. PubMed
Heck, G.L., Mierson, S., and DeSimone, J.A.: Salt taste transduction occurs through an amiloride-sensitive sodium transport pathway. Science 223: 403-405, 1984. PubMed
Heck, G.L., Persaud, K.C. and DeSimone, J.A.: Direct measurement of translingual epithelial NaCl and KCl currents during the chorda tympani taste response. Biophysical Journal, 55:843-857, 1989.PubMed
Ye, Q., Heck, G.L., and DeSimone, J.A. The anion paradox in sodium taste reception: Resolution by voltage-clamp studies. Science 254: 724-726, 1991. PubMed
DeSimone, J.A., Lyall, V., Heck, G.L., Phan, T-H.T., Alam, R.I., Feldman, G.M. and Buch, R.M. A Novel Pharmacological Probe Links the Amiloride-Insensitive NaCl, KCl, and NH4Cl Chorda Tympani Taste Responses. J. Neurophysiology, 86: 2638-2641, 2001. PubMed
Feldman GM, Mogyorosi A, Heck GL, DeSimone JA, Santos CR, Clary RA, Lyall V. Salt-evoked lingual surface potential in humans. J Neurophysiol. 2003 Sep;90(3):2060-4. PubMed
Lyall, V., Heck, G.L., Vinnikova, A.K., Ghosh, S., Phan ,T.H., Alam, R.I., Russell, O.F., Malik, S.A,, Bigbee, J.W., and DeSimone, J.A. The mammalian amiloride-insensitive non-specific salt taste receptor is a vanilloid receptor-1 variant. J. Physiology (London), 558: 147-159, 2004. PubMed
Lyall, V., T-H. T. Phan, S. Mummalaneni, M. Mansouri, G.L. Heck, G. Kobal, and J.A. DeSimone. Effect of nicotine on chorda tympani responses to salty and sour stimuli. J. Neurophysiol. 98: 1662-1674, 2007. DOI:10.1152/jn.00366.2007. PubMed