neurobiology, chemical senses
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. Further we want to understand how neuropeptides and hormones modulate these systems. Rather than studying all the sensory systems, my research focuses on one of the chemical senses, the sense of smell.
In the noses of most mammals there are 4 different areas in the nose that specialize in odor detection: the main olfactory epithelium, the Grueneberg ganglion, the septal organ and the vomeronasal organ. Of these the vomeronasal organ is the one most often involved in the detection of chemicals that are related to fear (predators) or socially relevant, such as pheromones (pheromones are those chemicals given off by a member of the same species that, when detected, elicit a particular behavior). The chemical receptors for the vomeronasal organ lie deep within the lumen of this sensory neuron-lined sac. These are neurons that have a single dendrite crowned at the apex with numerous microvilli. Embedded in the membrane of the microvilli are specific proteins or receptors that recognize certain chemical motifs such that they bind to certain molecules (sor of like a lock and key). The binding of an ordorant binds to its receptor protein, activates a tightly bound G protein inside the cell. This stimulates a second message cascade that leads to the transfer of pheromone/odor information to the central nervous system.
While there are several second messenger cascades that have been shown to be involved in odor transduction, such as cAMP in the main olfactory epithelium, in the vomeronasal sensory neurons appear to use a PLC pathway. When PLC is activated by a pheromone/odor one of the products, DAG directly opens a channel (TRPC2) that causes sodium and calcium to enter the cell. The influx of calcium activates a Ca-dependent chloride channel and amplifies the initial signal. This signal appears to be modulated by select chemicals signals, such as neuropeptides and hormones. This modulation is the focus of my current research.
Rona Delay, Suraj Cherian and Jonathan Vick (2010) Steroid hormones alter the responses of Mouse Vomeronasal sensory neurons. Invited presentation for "The 8th International Symposium on Molecular and Neural Mechanisms of Taste and Olfactory Perception" Fukuoka, Japan.
R.J. Delay and C. Yang (2010) Oxytocin modulated excitability and odor responses of mouse vomeronasal sensory neurons. Abstract on line. Society for Neuroscience, November 13-17 2010, San Diego, CA.