7 Your brain is walled off from the rest of your body by a l

7. Your brain is walled off from the rest of your body by a large \"fat\" layer (a fat layer is hydrophobic). This fat layer evolved in order to protect the brain; it hinders the transport of molecules entering the brain from the blood. The human body rapidly breaks down heroin into morphine. The pharmacological effects of both morphine and heroin (analgesia and sedation) occur when morphine interacts with the -opioid receptors in the brain. Heroin itself does not interact with the -opioid receptor. The LogP for heroin and morphine are 2.3 and 0.99, respectively If patient \"A\" receives an effective dose of morphine, while patient “B” receives the same mole amount of heroin, explain why patient \"B\" would feel less pain than patient “A”?

Solution

Patient B would feel less pain than patient A because heroin has a slightly different molecular structure which reflects heroins ability to transgress the blood brain barrier . This in effect means that heroin can penetrate the brain easily compared to morphine and have a greater effect. In fact heroin and morphine are pretty much the same in terms of effect the main difference is degree with heroin being 3 to 4 times stronger than morphine. In fact when heroin is injected into the bloodstream it automatically transforms into morphine once it hits the bloodstream.