A patient suffering from acute posttraumatic pain received an injection of morphine that brought him a significant relief. Which of the following mechanisms of action provided for antishock effect of morphine in this patient?

Answer options

1. Block of central cholinergic receptors
2. Stimulation of benzodiazepine receptors
3. Intensification of GABA-ergic reactions
4. Stimulation of opiate receptors
5. Inhibition of dopamine mediation

Explanation

Morphine binds to opioid receptors which block the transmission of nociceptive signals, signals pain-modulating neurons in the spinal cord, and inhibits primary afferent nociceptors to the dorsal horn sensory projection cells.