Emeriti

The research in my laboratory centers on understanding how the sensory receptors change or transduce information about the external world into a language the brain can understand. Rather than studying all the sensory systems, I have focused my research on one of the chemical senses, the sense of smell.

The receptors for the sense of smell (for mammals) lie deep within the nasal cavity. These olfactory receptors are neurons that have a single dendrite crowned at the apex with cilia. The cilia project into the lumen of the nasal cavity and it is here, on these cilia, that the odors first interact with the olfactory neurons. Embedded in the membrane of the cilia are specific proteins or receptors that recognize certain chemical motifs such that they bind to certain molecules (sort of like a lock and key). When an odorant is bound to its receptor protein that activates a tightly bound G protein inside the cell. This activates a second message cascade that leads to the transfer of odor information to the central nervous system.

Several second messenger cascades have been shown to be involved in odor transduction. Of these the best characterized is that involving cAMP. In this second messenger pathway the activation of the G-protein by the binding of an odorant to its receptors stimulates adenylyl cyclase to produce an increase in cAMP. The increase in cAMP activates a cAMP dependent non-selective cation channel which opens and the influx of sodium and calcium lead to a depolarization of the cell. However, not all odors excite the olfactory receptor cells. Some odors can inhibit the cell. What second messenger pathways mediate the inhibition is one of the focuses of my research. I am also quite interested in how the function of the olfactory receptor cells is modulated by a variety of different hormones and or neurotransmitters. Dopamine and gonadotropin releasing hormone (GnRH) have been shown to modulate olfactory receptor cell function but how this modulation occurs is completely unknown. My current research is directed at understanding the second messenger cascades involved in odor transduction and how these pathways are modulated by GnRH and dopamine.

 

Publications

Zhang, W and R. Delay (2007) Gonadotropin-releasing hormone modulates the voltage-activated sodium current in Necturus olfactory neurons. J Neuroscience Research 85:1656-1667.

Weeraratne D, M. Valentine, M. Cusick, R. Delay, and J. Van Houten (2006) M Plasma membrane Ca pumps of mouse olfactory Neurons. Chem Senses 31: 725-730.

Zhang, W and R. Delay (2004) Pulse stimulation by odors or IBMX/Forskolin elicits a transient potentiation of the odor response in isolated OSNs. Chem Senses 31:197-206

Delay, R. and D. Restrepo (2004) Odorant Responses of Dual Polarity are Mediated by cAMP in Mouse Olfactory Sensory Neurons. J Neurophysiol: 92: 1312-1319.

Delay, R. and V. Dionne (2003) Coupling between sensory neurons in the olfactory epithelium. Chem. Senses 28:807-815.

Delay, R. and V. Dionne (2002) Two Second Messengers Mediate Amino Acid Responses in Olfactory Sensory Neurons of the Mudpuppy, Necturus maculosus Chem. Senses 27:673-680.

Eisthen, H., R. Delay, C. Wirsig-Wiechmann and V. Dionne (2000) Neuromodulatory Effects Gonadotropin Releasing Hormone on Olfactory Receptor Neurons. J Neurosci.20:3947-3955.

Delay, R., A. Dubin and V. Dionne (1997) A cyclic nucleotide-gated chloride conductance in olfactory receptor neurons. J. Membrane Biol. 159:53-60

Delay, R.J., S.C. Kinnamon and S.D. Roper (1997) Serotonin modulates voltage-activated calcium currents in Necturus taste receptor cells. J. Neurophysiol. 77:2515-2524.

Nagai, T., D. J. Kim, R.J. Delay and S.D. Roper (1996) Neuromodulation of transduction and signal processing in the end organs of taste. Chem. Senses 21:353-365.

Delay, R.J.,A. MacKay-Sim and S. D. Roper (1994) Membrane properties of two types of basal cells in Necturus taste buds. J. Neurosci. 14:6132-6143.
 

Education

  • Ph.D. Colorado State University, Anatomy & Neurobiology Dept.
  • Postdoctoral: Boston University Marine Program, Woods Hole, MA

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