Subclass opioid receptors associated with the cardiovascular depression after traumatic shock and the antishock effects of its specific receptor antagonists.

The present available opioid receptor antagonists such as naloxone and naltrexone are not highly receptor selective. They may antagonize mu opioid receptors to affect the pain threshold of the patients with traumatic shock while they exert antishock effects. Therefore, they are not suitable for traumatic shock.