The effects of ropivacaine on sodium currents in dorsal horn neurons of neonatal rats.

Article Details

Citation

Copy to clipboard

Liu BG, Zhuang XL, Li ST, Xu GH

The effects of ropivacaine on sodium currents in dorsal horn neurons of neonatal rats.

Anesth Analg. 2000 May;90(5):1034-8.

PubMed ID

10781449 [ View in PubMed

]

Abstract

We used a whole cell patch clamp technique to study the effects of ropivacaine on rat dorsal horn neurons. Under voltage clamp, ropivacaine (10-400 microM) produced a dose-dependent inhibition of sodium current. From a holding potential (V(h)) of -80 mV, sodium currents evoked by test pulses to 0 mV were inhibited by ropivacaine with a mean drug concentration required to produce 50% current inhibition (IC(50)) value of 117.3 microM, which was more than the value of the bupivacaine (IC(50) 53.7 microM). The inhibition effect of ropivacaine was also voltage-dependent. Current evoked from a V(h) of -60 mV was inhibited by ropivacaine with a mean IC(50) value of 74.3 microM, which was less than that obtained at the V(h) of -80 mV. The inhibition effect of ropivacaine on sodium current was use dependent. Repeated activation by a train of depolarizing pulses (5 Hz, 20 ms) increased the inhibitory effects of ropivacaine. The ratio amplitudes of the 20th to the first pulse were 91.2% and 71.1%, respectively, in the absence and presence of ropivacaine (50 microM). Ropivacaine also produced a significant hyperpolarizing shift of 11 mV in the steady-state inactivation curve of sodium current. The inhibition of ropivacaine on the sodium channel may contribute to the mechanism of action of local anesthetics during epidural and spinal anesthesia.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Ropivacaine	Sodium channel protein type 10 subunit alpha	Protein	Humans	Yes	Inhibitor	Details