Abstract
Summary
1. In the spinal cat, small doses of morphine (5 mg per kg) enhanced two-neuron arc reflex discharges and depressed those traversing multineuron arcs. After the injection of larger doses (15 mg per kg), depression of multineuron arc discharges was followed by enhancement of these discharges.
2. Nembutal depressed both two-neuron and multineuron arc discharges. These effects were unaltered by previous injection of eserine or morphine plus eserine, and increased progressively with the dose of nembutal.
3. Ether depressed both two-neuron and multineuron reflex arc discharges.
4. Eserine enhanced two-neuron arc discharges, but had little effect on multineuron arc discharges. If, however, morphine had been injected previously, resulting in enhancement of two-neuron and depression of multineuron arc discharges, eserine caused enhancement of both types of reflex arc discharges.
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