Repeated cocaine administration (15 mg/kg/day) in vivo does not alter the membrane properties of motor cortex pyramidal neurons
The passive and active membrane properties measured by whole-cell current-clamp recordings of motor cortex pyramidal neurons from brain slices from saline- and cocaine-pretreated rats. Values represent the mean ± S.E.M. for the number of neurons indicated.
Pretreatment | 3 Days of Withdrawal | 2 to 3 Weeks of Withdrawal | ||||
|---|---|---|---|---|---|---|
| Saline | Cocaine | Saline | Cocaine | |||
| Number of neurons | 11 | 9 | 7 | 7 | ||
| Passive membrane properties | ||||||
| RMP (mV) | −70.34 ± 0.44 | −69.76 ± 0.24 | −70.13 ± 0.20 | −70.39 ± 0.29 | ||
| Input resistance (mΩ) | 68.03 ± 8.80 | 65.58 ± 4.21 | 67.66 ± 8.07 | 70.23 ± 6.43 | ||
| Active membrane properties | ||||||
| Current to generate action potential (nA) | 0.22 ± 0.02 | 0.21 ± 0.02 | 0.19 ± 0.01 | 0.21 ± 0.02 | ||
| Action potential threshold (mV) | −41.18 ± 1.08 | −41.16 ± 1.59 | −41.32 ± 0.80 | −39.94 ± 0.52 | ||
| Action potential amplitude (mV) | 81.75 ± 1.79 | 80.53 ± 1.85 | 79.70 ± 1.79 | 78.64 ± 1.88 | ||
| Action potential duration (ms) | 1.10 ± 0.04 | 1.18 ± 0.04 | 1.08 ± 0.05 | 1.12 ± 0.04 | ||
| AHP amplitude (mV) | 2.68 ± 0.63 | 3.10 ± 0.70 | 4.21 ± 0.92 | 4.13 ± 0.75 | ||