Objective: 

Although pain is among the homeostatic mechanisms just as hunger and thirst, chronic pain is a common problem that has a major impact on individual's everyday life. Due to poor knowledge about the mechanism(s) of the pain, the current treatment strategies are far from satisfactory and ethical issues require great reliance on animal and cellular models for deciphering neurobiological bases of nociception and pain.

Since the dorsal root ganglion (DRG) contains cell bodies of primary sensory neurons that convey information about a wide variety of sensory signals including noxious stimuli, DRG neurons in culture are well established model for the investigation of peripheral nociception. Cytosolic calcium [Ca²⁺]i, as a ubiquitous second messenger, involved in a wide range of neuronal functions including control of excitability and neurotransmitter release, and nociceptive signal transmission/transduction.

Methods: 

DRGs were removed from 1–2 day old (any gender) Wistar neonatal rats after decapitation and DRG neurons were isolated by enzymatic and mechanical procedures, and grown in the presence of nerve growth factor.

Results: 

By using whole cell mode of patch clamp and ratiometric fluorescence calcium imaging techniques, we investigated the effects of potential pain relieving agents including some anticonvulsants (levetiracetam, valproic acid), local anesthetics (levobupivacaine, bupivacaine) as well as endogenous agents (melatonin, orexin A and -B) in this nociceptive cellular model.

Conclusions: 

In conclusion, in vitro models including DRG's serve important tool for providing information on complex mechanisms of nociception and pain, and thereby provide basic evidence potentially useful for successful targeting and improvement in pain therapy.