Pain is an important clinical problem and there is growing evidence from both in vitro and in vivo studies that redox agents that modulate T-type voltage-gated calcium channels play an important role in sensory transmission. T-type calcium channels were first described in sensory neurons but progress in understanding the function of these channels in pain pathways has been hindered by the lack of selective pharmacological agents and modulators. In isolated rat sensory neurons, we recently reported that redox agents modulate T-currents but not other voltage- and ligand-gated currents thought to mediate pain sensitivity. Furthermore, the endogenous amino acid L-cysteine increased T-channel-mediated excitability in a novel subpopulation of capsaicin-sensitive sensory neurons. Thus, increase in excitability of sensory neurons that are enriched in T-type calcium channels by reducing agents may contribute to their hyperalgesic effect in vivo. These data for the first time strongly suggest a novel role for T-channels in peripheral pain transmission. On the basis of these preliminary results, we propose that peripheral T-type calcium channels can sensitize peripheral nociceptors and serve as general amplifiers of various nociceptive stimuli. To test this hypothesis, specific experiments will be performed focusing initially on the pharmacological and biophysical characterization of mechanisms underlying redox modulation of T-type calcium currents in rat sensory neurons in vitro. These experiments will set the stage for later studies designed to examine the molecular basis of redox modulation of T channels and physiological roles of T-currents in regulating the excitability of identified subsets of sensory neurons. Thus, studies of redox pharmacology and physiology of T-type calcium channels may help to elucidate roles of these channels in sensory processing. In addition, our results suggest an unexplored avenue for the development of potential novel therapies for pain control. ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM075229-03
Application #
7439132
Study Section
Neurotransporters, Receptors, and Calcium Signaling Study Section (NTRC)
Program Officer
Cole, Alison E
Project Start
2006-06-01
Project End
2010-05-31
Budget Start
2008-06-01
Budget End
2009-05-31
Support Year
3
Fiscal Year
2008
Total Cost
$282,126
Indirect Cost
Name
University of Virginia
Department
Anesthesiology
Type
Schools of Medicine
DUNS #
065391526
City
Charlottesville
State
VA
Country
United States
Zip Code
22904
Rose, K E; Lunardi, N; Boscolo, A et al. (2013) Immunohistological demonstration of CaV3.2 T-type voltage-gated calcium channel expression in soma of dorsal root ganglion neurons and peripheral axons of rat and mouse. Neuroscience 250:263-74
Lee, Jeonghan; Nelson, Michael T; Rose, Kirstin E et al. (2013) Redox mechanism of S-nitrosothiol modulation of neuronal CaV3.2 T-type calcium channels. Mol Neurobiol 48:274-80
Jacus, Megan O; Uebele, Victor N; Renger, John J et al. (2012) Presynaptic Cav3.2 channels regulate excitatory neurotransmission in nociceptive dorsal horn neurons. J Neurosci 32:9374-82
Orestes, Peihan; Bojadzic, Damir; Lee, Jeonghan et al. (2011) Free radical signalling underlies inhibition of CaV3.2 T-type calcium channels by nitrous oxide in the pain pathway. J Physiol 589:135-48
Nelson, Michael T; Milescu, Lorin S; Todorovic, Slobodan M et al. (2010) A modeling study of T-type Ca2+ channel gating and modulation by L-cysteine in rat nociceptors. Biophys J 98:197-206
Zamponi, Gerald W; Lewis, Richard J; Todorovic, Slobodan M et al. (2009) Role of voltage-gated calcium channels in ascending pain pathways. Brain Res Rev 60:84-9
Latham, Janelle R; Pathirathna, Sriyani; Jagodic, Miljen M et al. (2009) Selective T-type calcium channel blockade alleviates hyperalgesia in ob/ob mice. Diabetes 58:2656-65
Lee, Woo Yong; Orestes, Peihan; Latham, Janelle et al. (2009) Molecular mechanisms of lipoic acid modulation of T-type calcium channels in pain pathway. J Neurosci 29:9500-9
Jevtovic-Todorovic, Vesna; Covey, Douglas F; Todorovic, Slobodan M (2009) Are neuroactive steroids promising therapeutic agents in the management of acute and chronic pain? Psychoneuroendocrinology 34 Suppl 1:S178-85
Messinger, Richard B; Naik, Ajit K; Jagodic, Miljen M et al. (2009) In vivo silencing of the Ca(V)3.2 T-type calcium channels in sensory neurons alleviates hyperalgesia in rats with streptozocin-induced diabetic neuropathy. Pain 145:184-95

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