Tetrahydroaminoacridine (THA) reduces voltage-dependent calcium currents in rat sensory neurons.

Tetrahydroaminoacridine (THA) is a centrally active anticholinesterase that also interacts with neuronal K+ and Na+ channels and cardiac Ca2+ channels. The effects of THA on neuronal voltage-dependent Ca2+ channels are not known. We tested the effects of THA (25 nM-250 microM) on the Ca2+ current components of acutely dissociated rat nodose ganglion and dorsal root ganglion (DRG) neurons using the whole cell patch clamp recording technique. THA reduced the low-threshold (T) and high-threshold (N/L) Ca2+ current components in a concentration-dependent manner (IC50 approximately equal to 125 microM for T; approximately equal to 80 microM for N/L). Minimal current reduction was seen below approximately 10 microM. Our results show that THA reduces voltage-dependent Ca2+ currents in rodent sensory neurons suggesting another means by which THA may affect Ca(2+)-dependent physiologic processes.