ABSTRACT
These commonly utilised analgesics are thought to exert their effects through specifi c receptors spread throughout the body. The main opiate receptor is termed the mu-receptor. It is thought that opiate receptors allow cells to become hyperpolarised, reducing the excitability of cell membranes. This prevents the transmission of electrical nerve impulses triggered by painful stimuli. Opiates have many supplementary effects, due to the ubiquitous distribution of the mu-receptors. Cardiovascular effects include bradycardia and hypotension. Opiates are known to be potent depressants of respiration and protective airway reflexes. They are also associated with nausea, vomiting, itchiness and constipation.
