Membrane potentials and quantal contents of synaptic potentials in variously treated preparations
| Preparation | N | Rp (mV) | MEJP (mV) | EJP (mV) | M |
|---|---|---|---|---|---|
| Freshly isolated | 9 | 51 ± 2.8 | 0.93 ± 0.06 | 33 ± 1.7 | 109 ± 9.3 |
| FSK-treated | 9 | 51 ± 2.6 | 0.93 ± 0.07 | 38 ± 1.8 | 191 ± 28* |
| Cyc. A-treated | 8 | 50 ± 2.6 | 0.96 ± 0.06 | 34 ± 1.7 | 130 ± 26 |
| Intact, 2 hr | 9 | 49 ± 0.6 | 0.89 ± 0.05 | 30 ± 1.6 | 90 ± 9.5 |
| Severed, 2 hr | 8 | 49 ± 1.0 | 1.07 ± 0.08 | 16 ± 1.5* | 22 ± 2.6* |
| Severed, 2 hr, Cyt. D. | 7 | 49 ± 1.9 | 1.08 ± 0.10 | 33 ± 0.9 | 102 ± 14 |
Values represent the mean ± SEM. N, Number of preparations examined; Rp, resting membrane potential; MEJP, amplitude of spontaneous junctional potential; EJP, amplitude of nerve-evoked junctional potential; M, quantal content of synaptic potential, which was determined by dividing the mean EJP amplitude of each fiber by its mean MEJP amplitude and correcting for the nonlinearity of EJP amplitude; Freshly isolated, freshly isolated nontreated preparations; FSK-treated, preparations pretreated with 20 μm forskolin for 7 min; Cyc. A-treated, preparations pretreated with 10 μm cyclosporin A for 20 min; Intact, 2 hr, preparations with intact axons incubated for 2 hr; severed, 2 hr, preparations with axons severed and incubated for 2 hr; Severed, 2 hr, Cyt. D, preparations with axons severed and incubated for 2 hr in the medium containing 10 μm cytochalasin D.
* indicates a statistical difference from freshly isolated nontreated preparations at p < 0.01.