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Division of Natural Sciences & MathematicsDepartment of Biological Sciences

Faculty & Staff

Professor

John ("Jack") Kinnamon

Jack Kinnamon

Office:  SG Mudd 332

Office Phone: (303) 871-3467

Lab Phone: (303) 871-3659

E-mail: jkinnamo@du.edu

 

 

Degrees

  • 1968 BA, Biology - University of Delaware - Newark, DE
  • 1976 PhD, Biology - University of Georgia - Athens, GA

Research Interests

During the last two decades much has been learned about the functioning of taste cells through the identification of taste receptors (eg, T1Rs, T2Rs), functional markers (eg, alpha-gustducin, IP3R3, PLCb2), and synaptic proteins (eg, SNAP-25, syntaxin, synaptobrevin, synaptotagmin). Our laboratory has shown that classical synapses and synaptic proteins are associated with Type III cells. Although both small, clear vesicles and large, dense-cored vesicles are present at Type III synapses, the nature of their neurotransmitters remains a mystery. The situation with Type II cells is even more inscrutable. No classical synapses have been found associated with Type II cells, yet it is generally accepted that Type II cells transduce bitter, sweet and umami stimuli. In addition, recent studies indicate that Type II cells release ATP as a neurotransmitter. We have previously described putative functional contacts for Type II cells, including large, atypical mitochondria which are present at close appositions between taste cells and intragemmal nerve processes.

Magnified image of taste bud cells

Triple-stained immunofluorescence image showing two rat taste buds. The red structures are taste cells and nerve processes containing syntaxin, a protein involved in taste cell-nerve communication. The blue cells contain gustducin, a protein involved in the perception of bitter and sweet taste. Cellular nuclei are stained green. (Image taken by Dr. Ruibiao Yang.) This image was used for the cover of the April 23, 2007 issue (Vol. 502, No. 6) of the Journal of Comparative Neurology.

We propose to examine communication in taste buds by using immunofluorescence and immunoelectron microscopy with colloidal gold labeling or silver-intensified nanogold immunoelectron microscopy to elucidate the nature of functional contacts in taste buds of the mouse.

The goals of my laboratory's research are to answer the following questions:

  • Aim 1. What is the nature of the contacts between Type II cells and nerve processes?
  • Aim 2. Do Type II cells form specialized contacts with other taste cells?
  • Aim 3. What is the nature of the contacts formed by Type III cells with Type II cells and nerve processes?

The results obtained from these studies will help to elucidate the basic mechanisms underlying taste, one of the most complex of the senses. These results will provide an important basis for understanding and treating diseases of the gustatory system. Such an understanding of gustation in health and disease will facilitate future studies of other sensory systems and the nervous system in general.

Link to Kinnamon's publications through PubMed