Ans. is 'c' i.e., Anticholinergic drug Actions of anticholinergic drugs l.CNSo Atropine has an overall CNS stimulant action, while Hyoscine produces CNS depression,o Due to its amnestic and CNS depressant action, hyoscine induces "twilight sleep " and has been used as lie detector or truth serum in suspects.o Atropine stimulates medullary centres - vagal, respiratory', vasomotor.o Atropine depresses vestibular excitation and has antimotion sickness property'.o Transdermal patch of scopolamine (hyoscine), applied behind the pinna is used to prevent motion sickness.o Atropine suppresses tremor and rigidity' of parkinsonism by blocking relative cholinergic overactivity in basal ganglia,o Central cholinergic agents like benztropine, benzhexol (trihexiphenidyl) and biperiden are drug of choice for drug induced parkinsonism.2. CVSo The most prominent effect of atropine is to cause tachycardia.o On im/sc injection transient initial bradycardia often occurs due to blockade of muscarinic autoreceptors (Ml) on vagal nerve endings augmenting ACH release.o Atropine abbrevates refractory' period of A-V node and facilitates A-V conduction, PR interval is shortened,o Atropine does not have any consistent or marked effect on BP.o Atropine can be used in arrhythmias like AV block and digitalis induced arrhythmia.3. Eyeo Atropine causes mydriasis, abolition of light reflex and cycloplegia (paralysis of accomodation),o Due to dilatation of iris, iris comes closer to angle of anterior chamber and trabecular meshwork at the base of ciliary muscle is closed -| aqueous out flow - | IOT.o Atropine increases intraocular tension - Contraindicated in glaucoma.4. Smooth muscleso Tone and amplitude of contractions of stomach and intestine are reduced, constipation may occur,o Atropine causes bronchodilatation and reduced airway resistance, especially in COPD and asthma patients,o Atropine relaxes urinary' bladder, urinary retention may occur,o Effect on biliary tract is less marked and on uterus is minimal.5. Glandso Atropine decreases sweat, salivary', tracheobronchial and lacrimal secretion,o Atropine decreases secretion of acid, pepsin and mucus in the stomach,o Intestinal and pancreatic secretions are not significantly reduced,o Bile production is not affected.6. At higher doses atropine causes rise in body temperature - Contraindicated in children due to risk of hyperthermia.7. Atropine has mild anaesthetic property' on the cornea.