AIM: To develop a tool for detailed analysis of spirally acting anesthetic and analgesic agents. METHODS: Studies were done on visually identified motor neurons in 400 uuuuuuuum thick spinal cord slices from 14-23 d old rats using patch clamp techniques. Ethanol was used as a prototype general anesthetic agent. RESULTS: Cell bodies in the ventrolateral horn identified as motor neurons by retrograde fluorescent labeling had a mean dimension of 32 ± 5 /Mm (x ± s, n = 25). Mean resting potential was - 62. 8 ± 2. 4 mV; input resistance was 44±24 MΩ (n = 19). Threshold was -44± 7 mV, and action potential amplitude 101 ± 9 mV from baseline. Ethanol concentrations at and below 50-200 mmol/L decreased motor neuron excitability to the injected current; there was no effect on resting potential, but a variable reversible increase in input resistance. Ethanol re-versibly depressed the excitatory postsynaptic potential, with a dose-response relationship similar to that previously observed for the population e AIM: To develop a tool for detailed analysis of spirally acting anesthetic and analgesic agents. METHODS: Studies were done on identifying motor neurons in 400 uuuuuuuum thick spinal cord slices from 14-23 d old rats using patch clamp techniques. Ethanol was used as a prototype general anesthetic agent. RESULTS: Cell bodies in the ventrolateral horn identified as motor neurons by retrograde fluorescent labeling had a mean dimension of 32 ± 5 / Mm (x ± s, n = 25). Mean resting potential was - 62. 8 ± 2. 4 mV; input resistance was 44 ± 24 MΩ (n = 19). Threshold was -44 ± 7 mV and action potential amplitude 101 ± 9 mV from baseline. Ethanol concentrations at and below 50-200 mmol / L motor neuron excitability to the injected current; there was no effect on resting potential, but a variable reversible increase in input resistance. Ethanol re-versibly depressed the excitatory postsynaptic potential, with a dose-response relationship similar to that previously observed r the population e