Passive and active membrane properties of isolated control and vagotomized nodose neurons
| Contralateral Control | Control Animal | Vagotomy | |
|---|---|---|---|
| Passive properties | |||
| R in, MΩ | 371 ± 21 (67) | 432 ± 29 | 284 ± 20* |
| C m, pF | 34 ± 1.4 | 32 ± 1.0 | 46 ± 1.4† |
| E m, mV | −50 ± 0.8 (67) | −49 ± 1.0 (44) | −53 ± 0.8 (65)* |
| AP characteristics | |||
| AP duration, ms | 1.3 ± 0.1 (65) | 1.7 ± 0.2 | 1.2 ± 0.1 (64) |
| AP overshoot, mV | 49 ± 1.5 (65) | 47 ± 1.3 | 40 ± 2.2 (64)* |
| Peak hyperpolarization, mV | −71 ± 0.5 (65) | −71 ± 0.3 | −68 ± 0.6 (64)† |
| Firing properties | |||
| AP rheobase, pA | 81 ± 20 | 103 ± 17 | 264 ± 19† |
| Absolute (APs) | 16.9 ± 2.3 | 11.4 ± 1.8 | 2.6 ± 0.6† |
| 1 times threshold (APs) | 1.8 ± 0.2 | 1.7 ± 0.2 | 1.1 ± 0.2‡ |
| 2 times threshold (APs) | 5.1 ± 0.4 | 3.7 ± 0.5 | 1.7 ± 0.4 (65)† |
| 3 times threshold (APs) | 8.3 ± 1.3 (66) | 5.6 ± 0.8 | 2.3 ± 0.4 (65)† |
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Values are means ± SE; numbers in parentheses are number of neurons for each measurement when different from the total number of neurons in that group. Number of neurons in Contralateral Control is 68, in Control Animal is 46, and in Vagotomy is 66. Passive and active membrane properties of isolated control and vagotomized nodose neurons. R in, membrane input resistance;C m, membrane capacitance;E m, resting membrane potential; AP duration, the width the action potential (AP) measured at 0 mV; AP overshoot, the peak voltage (above 0 mV) recorded during the AP; Peak hyperpolarization, the most negative value of the membrane potential following a single AP; AP rheobase, the minimum amount of current required to evoke a single AP; Absolute firing, the maximum number of APs fired in response to any single 750-ms depolarizing current step of 0.1–0.9 nA magnitude (in 0.1-nA increments); 1, 2, and 3 times threshold, the number of APs fired by an NGN during a 750-ms depolarizing current step of a magnitude 1, 2, or 3 times its rheobase, respectively. Values of vagotomized NGNs were compared to values of control NGNs using 2-way ANOVA (as described in methods). * P < 0.01. † P < 0.001. ‡ P < 0.05.