Answer:
1. A drug that raises the resting membrane potential of pain sensing neurons
2. A drug that opens Cl- channels at rest.
Step-by-step explanation:
The pain is felt when the sensation of pain is perceived by the brain that is the sensation lies in the neurotransmission of the pain impulse to the brain. The drugs are prepared in a way that interferes with the transmission of the impulse.
The action potential in a neuron is generated when the neuron membrane is depolarised therefore the drug which could block the neuron from depolarization will be most effective.
Also, the drug which could open the chlorine ions will be most effective as the chloride ion influx will cause hyperpolarization which will be difficult to be depolarised.
Thus, the selected options are correct.