Cardiovascular responses to injections of cholinomimetic drugs into the cerebral ventricles of unanaesthetized dogs.

摘要: 1. The cardiovascular and behavioural effects of cholinomimetic drugs injected through a cannula chronically implanted into lateral cerebral ventricle were examined in unanaesthetized dogs.2. Acetylcholine (ACh) (10-20 mug) produced an increase arterial pressure heart rate, the dogs became more alert, moved their heads, licked swallowed then drowsy.3. responses to ACh potentiated by intraventricular physostigmine (5 mug), abolished atropine (100 but unaffected mecamylamine (250 mug). reproducible on any one day if injections given again after 30 min interval tolerance developed when was repeatedly over periods several days.4. Methacholine (40 similar longer duration. methacholine mug).5. Nicotine (20-60 biphasic response initial brief pressor tachycardia followed secondary rate which greater magnitude associated with restlessness vomiting.6. nicotine prior injection not repeated same could be few days allowed elapse between injections.7. An increased occurred during comparable intravenous infusion noradrenaline pronounced reflex bradycardia resulted.8. results indicate that activation both muscarinic nicotinic cholinergic mechanisms leads conscious dog although site action peripheral have been determined.