To define a method to “Determine the effect and site of action of strychnine”.
* Healthy Frog.
Strychnine is highly toxic,colorless,crystalline alkaloid cause killing of small vertebrates e.g, dogs,rodents because its site of action is spinal cord. Symptoms of severity:
Severe nausea and vomiting ,convulsions of all muscle groups which become more longer and shortly space.Loss of consciousness,poster become arc shaped.Poster may be opinthotonus or pleurothotonus. LD50:
1. For rodents 0.16mg/Kg.
2. For Humans 1-2mg/kg.
Mechanism Of action (strychnine):
Strychnine is a neurotoxin and death occurs due to asphyxia(respiratory failure).Motor nerves are present on spinal cord,they control the muscle contractions. Strychnine act on the glycine receptors,these are inhibitory receptors when they stimulate chloride channel open,chlorine move inside and cause hyperpolarization normally.But strychnine block these glycine receptors or acts as antagonist for these receptors.As a result chloride channel does not open and no hyperpolarization and excitatory effect on muscles is not stopped and produce forceful contractions which are of longer duration and shortly space,ultimately paralysis of respiratory muscles which lead to death. Procedure:
* Take a healthy frog,check its rightening reflex,conditions of muscles and extension thurst. * Check also respiratory rate of frog.
* After this,administer solution(1mg/Kg) of drug through subcutaneous route in abdominal cavity,2ml water is used for reconstitution of drug. * Observe the effects of drug on frog and discuss the results. Uses:
It is used as a:
* First time in history,in 1912 it was used by an athlete as muscular excitant. * It is also an antagonist of acetalcholine and...