Table 1.
Summary of effects of local cathodal polarization on various tests in the cat and rat spinal cord
| Area as a percentage of control (± sem) | ||||||
|---|---|---|---|---|---|---|
| Number of | Number of | During last | Twenty minutes after | Statistical | ||
| Tests | tests | animals | DC period | the last polarization | significance | |
| Rat | ||||||
| (a) | Responses of cutaneous afferents | 8 | 6 | 154.2 ± 12.1 | 135.5 ± 8.2 | See Fig. 1 |
| (b) | Field potentials from cutaneous afferents | 8 | 7 | 64.2 ± 7.5 | 78.1 ± 6.1 | See Fig. 7 |
| (c) | Directly evoked motoneuron responses | 7 | 6 | 166.3 ± 27.3 | 116.5 ± 9.7 | Not significant |
| Cat | ||||||
| (d) | Responses of group la afferences | 7 | 5 | 168.3 ± 23.2 | 150.5 ± 19.5 | See Fig. 2 |
| (e) | Field potentials from group la afferents | 8 | 3 | 128.9 ± 8.3 | 120.9 ± 10.1 | See Fig. 5 |
| (f) | Monosynaptic EPSPs in motoneuronst | 18 | 2 | 114.2 ± 7.0 | 119.7 ± 18.0 | |
| (g) | Monosynaptic reflex | 7 | 3 | 191.1 ± 16.6 | 161.9 ± 13.9 | See Fig. 6 |
| (h) | Presynaptic volleys | 9 | 3 | 98.0 ± 4.4 | 96.2 ± 3.4 | Not significant |
| (i) | Directly evoked motoneuron responses | 9 | 5 | 148.6 ± 8.1 | 117.5 ± 6.1 | Not significant |
(a) Stimuli and DC polarization were applied in the dorsal horn. Activity in cutaneous afferents was recorded from the Sur nerve. (b) Field potentials were evoked in the dorsal horn by stimulating the Sur nerve. DC was applied via recording electrodes in the dorsal horn. (c) Stimuli and DC polarization were applied in the DP motor nucleus. Motoneuronal discharges were recorded from the DP nerve after transection of the L2–L6 dorsal roots. (d) Stimuli and DC polarization were applied in the PBST and/or GS motor nuclei. Activity in Ia afferents was recorded from the dorsal roots or from the PBST or GS nerves when the DRs were transected. (e) Field potentials were evoked within motor nuclei by stimulating the PBST and/or GS nerves. DC was applied via recording electrodes in the motor nuclei. (f) Monosynaptic EPSPs were evoked in motoneurons by stimulating the PBST or GS nerves. DC was applied in the same motor nucleus. EPSPs were recorded during and after only one period of polarization. (g) Monosynaptic reflexes were evoked by stimulating the PBST and/or GS nerves. They were recorded from the S1 and/or L7 VR. DC was applied in the PBST and/or GS motor nuclei. (h) Presynaptic volleys from group Ia afferents preceding field potentials evoked in motor nuclei were recorded at the same time as the field potentials in series (e). (i) Stimuli and DC polarization were applied in the PBST and/or GS motor nuclei. Motoneuronal discharges were recorded from the PBST and/or GS nerves after transection of the L7 and S1 VRs or from the VRs. In the 2nd column, the ‘number of tests’ indicates the number of the series of records in which DC effects were evaluated. As a rule, except for those in (f) (see text), they were obtained either in separate experiments or from the left and right side in the same rat.