Narcotic means to make numb originally refferd medically to any psychoactive drugs with numbing or paralysing property.
– in United state it has since become associated with opiates and opioid commanly morphine and heroin as well as derivatives of many other compounds found within raw opium latex.
-The primary 2 are morphine and codeine.
Analgesic are drug that relieve pain there are two types,
(1) Non narcotic for mild pain.
Eg.- spirine and paracetamol.
(2) Narcotics analgesic for severe pain.
Eg.- Morphine and heroin.
Narcotics analgesic tends to be opioids they bind to opioids receptors which are G-protien coupled receptors distributed in brain and spinal cord, digestive tatct, peripheral nuerons.
There are three types of opioids receptors.
(2) Delta receptors.,
– They are endogenous opioids donot bind specifically to any particular opioids receptors.receptor binding to the opioids causes a cascade leading to the channel opening and hyperpolarization of the neurons.
– Hyperpolarization can leads to post synaptic neural inhibition and pre synaptic inhibition of the neurotransmitter release..
– Post synaptic neural inhibition can reduse analgesia and central hyperactivity may reduces its efficiency.
The machanism of kappa receptors is slightly different than My and Delta channales.