Respiratory centre depression is caused by all of the following, Except:

Answer is B (Strychnine): Strychnine is a CNS stimulant. It does not cause respiratory depression Gelsemium causes Respiratory Depression Gelsemium (ergot type alkaloid) is a CNS depressant. 'Symptoms of toxicity include difficulty in the use of voluntary muscles, muscle rigidity and weakness, dizziness, dry mouth, visual disturbances, tremor of extremities, sweating, conrulsions and respiratory depression. With large doses, paralysis and death from respiratory failure can occur' - 'The Encyclopedia of poisons and Antidotes' 3rd/112 Opium and Barbiturates are known to cause Respiratory Depression. Barbiturates cause respiratory depression in high doses (KDT6th/39 I) (Barbiturates are CNS Depressants) Opiates depress respiratory centre in a dose dependant manner (KDT 6th/454)