M3 receptor subtype is located:

Correct Answer: C

Rationale: The correct answer is C - On effector cell membranes of glandular and smooth muscle cells. The M3 receptor subtype is a muscarinic acetylcholine receptor, which is primarily located on the effector cell membranes of glandular and smooth muscle cells. This receptor subtype plays a key role in mediating parasympathetic responses in these cells. A: In the myocardium - This is incorrect as the M2 receptor subtype is predominantly located in the myocardium, not the M3 subtype. B: In sympathetic postganglionic neurons - This is incorrect as muscarinic receptors are not typically found in sympathetic neurons. D: On the motor end plates - This is incorrect as nicotinic acetylcholine receptors, not muscarinic receptors, are located on motor end plates.

Correct Answer: B

Rationale: The correct answer is B: It is used to treat bronchospasm. Dobutamine is a beta1-selective synthetic catecholamine used for its positive inotropic effects in conditions like heart failure. Choice A is correct as dobutamine is beta1-selective. Choice C is incorrect as dobutamine can increase atrioventricular conduction. Choice D is incorrect as dobutamine can cause changes in heart rate and systolic pressure. Therefore, the correct answer is B because dobutamine is not used to treat bronchospasm.

Correct Answer: D

Rationale: Propranolol is a non-selective beta-blocker, used in cardiovascular diseases, hyperthyroidism, and migraine headache. However, it is contraindicated in bronchial asthma due to its potential to induce bronchoconstriction. Propranolol can worsen asthma symptoms by blocking beta-2 receptors in the lungs, leading to bronchoconstriction and exacerbation of asthma. Therefore, the correct answer is D. Choices A, B, and C are incorrect as propranolol is commonly used for these conditions due to its beneficial effects on heart rate, blood pressure, and migraine prevention.

Correct Answer: C

Rationale: The correct answer is C because hypnotic benzodiazepines are known to decrease both REM and slow wave sleep in a dose-dependent manner. This is due to their ability to suppress rapid eye movement (REM) sleep and slow wave sleep stages. Benzodiazepines have a sedative effect on the central nervous system, leading to a reduction in overall sleep quality and disruption of normal sleep architecture. Choice A is incorrect because benzodiazepines do not increase REM or slow wave sleep. Choice B is incorrect because benzodiazepines do alter sleep patterns. Choice D is incorrect as it states an increase in REM sleep, which is not true for benzodiazepines.

Correct Answer: C

Rationale: The correct answer is C: Valproate. Valproate is effective for both focal and generalized seizures due to its broad-spectrum antiseizure properties. It works by enhancing the inhibitory neurotransmission in the brain, affecting multiple seizure types. Phenytoin (A) and Carbamazepine (B) are more commonly used for focal seizures, while Topiramate (D) is effective for both focal and generalized seizures but is not as broad-spectrum as Valproate. Valproate's mechanism of action and efficacy across seizure types make it the most suitable choice for treating both focal and generalized seizures.