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 antishock effect of morphine in this patient?

Answer options

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

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.