| Title: | Heterogeneity of voltage- and chemosignal-activated response profiles in vomeronasal sensory neurons |
| Author(s): | Labra A; Brann JH; Fadool DA; |
| Address: | "Department of Biological Science, Programs in Neuroscience and Molecular Biophysics, Florida State University, Tallahassee, 32306, USA" |
| ISSN/ISBN: | 0022-3077 (Print) 1522-1598 (Electronic) 0022-3077 (Linking) |
| Abstract: | "Liolaemus lizards were explored to ascertain whether they would make an amenable model to study single-cell electrophysiology of neurons in the vomeronasal organ (VNO). Despite a rich array of chemosensory-related behaviors chronicled for this genus, no anatomical or functional data exist for the VNO, the organ mediating these types of behaviors. Two Liolaemus species (L. bellii and L. nigroviridis) were collected in Central Chile in the Farellones Mountains and transported to the United States. Lizards were subjected to hypothermia and then a lethal injection of sodium pentabarbitol prior to all experiments described in the following text. Retrograde dye perfusion combined with histological techniques demonstrated a compartmentalization of the proportionally large VNO from the main olfactory epithelium (MOE) in cryosections of L. bellii. SDS-PAGE analysis of the VNO of both species demonstrated the expression of three G protein subunits, namely, G(alphao), G(alphai2), and G(beta), and the absence of G(alphaolf), G(alpha11), and G(q), the latter of which are traditionally found in the MOE. Vomeronasal (VN) neurons were enzymatically isolated for whole cell voltage-clamp electrophysiology of single neurons. Both species demonstrated a tetrodotoxin (TTX)-sensitive, rapidly inactivating sodium current and a tetraethylammonium (TEA)-sensitive potassium current that had a transient and sustained component. VN neurons were classified into two types dependent on the ratio of sodium over sustained potassium current. VN neurons exhibited outward and inward chemosignal-evoked currents when stimulated with pheromone-containing secretions taken from the feces, skin, and precloacal pores. Fifty-nine percent of the neurons were responsive to at least one compound when presented with a battery of five different secretions. The breadth of responsiveness (H metric) demonstrated a heterogeneous population of tuning with a mean of 0.29" |
| Keywords: | "Anesthetics, Local/pharmacology Animals Blotting, Western/methods Cell Count/methods Chemoreceptor Cells/*physiology Dextrans/metabolism Electric Conductivity Female GTP-Binding Proteins/metabolism Histocytochemistry Lizards Male Membrane Potentials/drug;neuroscience;" |
| Notes: | "MedlineLabra, Antonieta Brann, Jessica H Fadool, Debra A eng F31-DC-006153/DC/NIDCD NIH HHS/ R15 DC003318-01/DC/NIDCD NIH HHS/ R01 DC003387/DC/NIDCD NIH HHS/ P01 HL114453/HL/NHLBI NIH HHS/ R01 HL096376/HL/NHLBI NIH HHS/ F31 DC006153/DC/NIDCD NIH HHS/ R01 HL098174/HL/NHLBI NIH HHS/ Comparative Study Research Support, N.I.H., Extramural Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S. 2005/06/24 J Neurophysiol. 2005 Oct; 94(4):2535-48. doi: 10.1152/jn.00490.2005. Epub 2005 Jun 22" |
