This is an application for a K award (Research Career Development Award) from NIDA. The applicant is an anesthesiologist who is interested in studying the role of Ca2+ channels in sensory transmission including nociception with the long term goal being to determine the potential of Ca2+ channel blockers for better management of chronic pain. The applicant has chosen for his primary sponsor Charles F. Zorumski, M.D., a psychiatrist and neuroscientist who is a leader in the fields of glutamate research and CNS synaptic physiology. He will be co-sponsored by Christopher J. Lingle, Ph.D., an established neuroscientist and biophysicist who is pursuing research studies of Ca2+ channels that are relevant to the applicant's career goals. Additionally, one consultant will offer help in applicant's training and guidance. Min Zhuo, Ph.D., a neuroscientist with expertise in cellular electrophysiology, will provide training in spinal cord slice preparation. The applicant's goal is to acquire expertise to launch an independent career in pain research in the future. The applicant's research proposal addresses the role of multiple Ca2+ channels in sensory and nociceptive pathways in DRG and spinal cord. Even though voltage gated Ca2+ channels have long been recognized as targets for analgesic, anesthetic and anticonvulsant agents, progress in understanding the action of these channels on specific targets within sensory pathways has been impeded by the lack of selective tools to study their pharmacology. In the past two years, working on acutely dissociated rat DRG cells, the applicant has identified a novel selective antagonist for T-type Ca2+ channels, a neurosteroid (+)-ECN, which has minimal effects on other voltage- and receptor-gated channels. Another neurosteroid, (+)-ACN, shows remarkable selectivity for Q-, and R-subtypes of HVA Ca2+ channels and is a promising new tool to study HVA channels. Additionally, one of the most effective agents for treatment of neuropathic pain, the anticonvulsant phenytoin, blocks T-type current in DRG neurons in clinically relevant concentrations. The applicant proposes to follow up these findings with additional studies aimed at further clarifying the mechanisms and targets for these agents in acutely dissociated labeled spinothalamic dorsal horn neurons, isolated dendrites of dissociated dorsal horn neurons and their effects on synaptic transmission in DRG-dorsal horn co-cultures.

Agency
National Institute of Health (NIH)
Institute
National Institute on Drug Abuse (NIDA)
Type
Clinical Investigator Award (CIA) (K08)
Project #
5K08DA000428-02
Application #
6378308
Study Section
Human Development Research Subcommittee (NIDA)
Program Officer
Thomas, David D
Project Start
2000-08-16
Project End
2001-08-31
Budget Start
2001-08-01
Budget End
2001-08-31
Support Year
2
Fiscal Year
2001
Total Cost
$10,728
Indirect Cost
Name
Washington University
Department
Anesthesiology
Type
Schools of Medicine
DUNS #
062761671
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Pathirathna, Sriyani; Covey, Douglas F; Todorovic, Slobodan M et al. (2006) Differential effects of endogenous cysteine analogs on peripheral thermal nociception in intact rats. Pain 125:53-64
Joksovic, Pavle M; Nelson, Michael T; Jevtovic-Todorovic, Vesna et al. (2006) CaV3.2 is the major molecular substrate for redox regulation of T-type Ca2+ channels in the rat and mouse thalamus. J Physiol 574:415-30
Todorovic, Slobodan M; Jevtovic-Todorovic, Vesna (2006) The role of T-type calcium channels in peripheral and central pain processing. CNS Neurol Disord Drug Targets 5:639-53
Pathirathna, Sriyani; Brimelow, Barbara C; Jagodic, Miljen M et al. (2005) New evidence that both T-type calcium channels and GABAA channels are responsible for the potent peripheral analgesic effects of 5alpha-reduced neuroactive steroids. Pain 114:429-43
Pathirathna, S; Todorovic, S M; Covey, D F et al. (2005) 5alpha-reduced neuroactive steroids alleviate thermal and mechanical hyperalgesia in rats with neuropathic pain. Pain 117:326-39
Joksovic, Pavle M; Bayliss, Douglas A; Todorovic, Slobodan M (2005) Different kinetic properties of two T-type Ca2+ currents of rat reticular thalamic neurones and their modulation by enflurane. J Physiol 566:125-42
Nelson, Michael T; Joksovic, Pavle M; Perez-Reyes, Edward et al. (2005) The endogenous redox agent L-cysteine induces T-type Ca2+ channel-dependent sensitization of a novel subpopulation of rat peripheral nociceptors. J Neurosci 25:8766-75
Todorovic, Slobodan M; Pathirathna, Sriyani; Meyenburg, Adam et al. (2004) Mechanical and thermal anti-nociception in rats after systemic administration of verapamil. Neurosci Lett 360:57-60
Todorovic, Slobodan M; Meyenburg, Adam; Jevtovic-Todorovic, Vesna (2004) Redox modulation of peripheral T-type Ca2+ channels in vivo: alteration of nerve injury-induced thermal hyperalgesia. Pain 109:328-39
Todorovic, Slobodan M; Pathirathna, Sriyani; Brimelow, Barbara C et al. (2004) 5beta-reduced neuroactive steroids are novel voltage-dependent blockers of T-type Ca2+ channels in rat sensory neurons in vitro and potent peripheral analgesics in vivo. Mol Pharmacol 66:1223-35

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