Journal
JOURNAL OF NEUROSCIENCE RESEARCH
Volume 76, Issue 5, Pages 713-722Publisher
WILEY
DOI: 10.1002/jnr.20109
Keywords
hyperpolarization-activated; cyclic nucleotide-gated channel; I-h; dorsal root ganglion; ZD7288
Categories
Ask authors/readers for more resources
The large, medium-sized, and small neurons of the dorsal root ganglion (DRG) have different functions in the processing of various senses. Hyperpolarization-activated, cyclic nucleotide-gated channels (HCN) contribute greatly to neuronal excitability. In the present study, which used whole-cell patch clamp techniques and immunohistochemical staining methods, the electrophysiological properties of DRG neurons were systematically compared, and the roles of HCN-1, -2, and -4 were examined. The main results were as follows. 1) The large neurons had significantly higher V-0.5 values (membrane potential at which the HCN channels were half-activated) and shorter time constants (T) than small or medium-sized DRG neurons. However, large DRG neurons had higher I-h density (HCN neuron current). 2) HCN-1 was found predominantly, but not exclusively, in large and medium-sized DRG neurons; HCN-2 was found in all DRG neurons; and HCN-4 was poorly visualized in all DRG neurons. HCN-1 and HCN-2 were colocalized in large and medium-sized neurons with immunostaining of adjacent sections. In the dorsal horn of the spinal cord, HCN-1, HCN-2, and HCN-4 were all expressed in laminae I-IV, although HCN-1 was not detectable in lamina II. 3) Blockade of 1, current in DRG neurons caused a significant decrease in V0.5, resting membrane potential, and repetitive firing number of action potential and a significant increase in time of rising phase of action potential. These results suggest that the different HCN channels in the three types of DRG neurons might contribute to their differential electrophysiological properties. (C) 2004 Wiley-Liss, Inc.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available