This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Neurotransmitters, Subject name: Physiology
Endorphin release causes - 
Select and explain. 
A. Analgesia, B. Allodynia, C. Hyperalgesia, D. None of the above
A: Analgesia
Answer: A: Analgesia 
Explanation: Ans. is 'a' i.e., Analgesia o Primary action of endorphin (b-endorphin) is to inhibit pain.o Neurons containing b--endorphin descend from the hypothalamus to terminate on periaquenductal gray matter of midbrain. Periaqueductal gray matter send enkephalinergic and dynorphinergic neuron to medulla to inhibit pain by stimulating raphe nucleus.