This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Forensic Medicine
Which among the following poison acts as a spinal poison? 
Select and explain. 
A. Strychnine, B. Organophosphorus, C. Oleander, D. Cannabis
A: Strychnine
Answer: A: Strychnine 
Explanation: Strychnine competitively blocks ventral horn motor neuron postganglionic receptor sites in the spinal cord and prevents the effects of glycine. Widespread inhibition in the spinal cord results in 'release' excitation. The action is paicularly noted in the anterior horn cells. It stimulates the cerebral coex. Ref: The Essentials of Forensic Medicine and Toxicology by KS Narayan Reddy, 27th edition, Page 545.