Membrane properties: 3 week withdrawal from intraperitoneal administration
| Treatment | Saline w/d | Cocaine w/d | Saline w/d + cocaine | Cocaine w/d + cocaine | Acute cocaine |
|---|---|---|---|---|---|
| Number of cells | n = 12 | n = 16 | n = 16 | n = 16 | n = 12 |
| Break-in RMP (mV) | −73.52 ± 0.8 | −74.5 ± 0.7 | −76.3 ± 0.5* | −77.9 ± 0.8** | −75.3 ± 0.7 |
| Stabilized RMP (mV) | −81.3 ± 0.7 | −81.1 ± 0.5 | −83.2 ± 0.6 | −83.3 ± 0.6 | −81.1 ± 0.9 |
| Ri at −100 pA (MΩ) | 137.6 ± 7.5 | 111.9 ± 5.1 | 101.8 ± 3.0 | 128.0 ± 2.5 | 103.1 ± 3.6 |
| Ri at +100 pA (MΩ) | 236.4 ± 5.3 | 211.7 ± 9.7 | 233.6 ± 6.6 | 249.3 ± 7.6 | 218.9 ± 8.1 |
| Latency, 1st spike (ms) | 188 ± 27 | 182 ± 34 | 174 ± 14 | 176 ± 14 | 171 ± 12 |
| Rheobase (pA) | 120 ± 15 (n = 5) | 142 ± 11 (n = 8) | 118 ± 10 (n = 6) | 118 ± 16 (n = 7) | 137 ± 7 (n = 4) |
| AP threshold (mV) | −31.3 ± 0.9 | −32.2 ± 1.2 | −32.3 ± 0.5 | −31.8 ± 0.9 | −30.9 ± 0.6 |
RMP, Resting membrane potential; Ri, input resistance; AP, action potential; Rheobase, minimal current that elicits an action potential along the duration (300 ms) of the test step. RMP (mV):
↵*p < 0.05, saline w/d i.p. vs saline w/d i.p. + cocaine i.p.;
↵**p < 0.05, cocaine w/d i.p./cocaine w/d + cocaine i.p.