A 42-year-old woman with generalized anxiety disorder presents with recurrent episodes of palpitations, tremor, and diaphoresis triggered by work-related stress. Vital signs show heart rate 96 bpm, blood pressure 138/86 mmHg, and respiratory rate 18 breaths/min. Physical examination confirms bilateral fine tremor and diaphoresis. Thyroid function tests and urine catecholamines are normal. She is started on propranolol. At follow-up 4 weeks later, she reports marked improvement in palpitations and tremor but continues to experience intrusive thoughts, worry, and difficulty concentrating. Which of the following best explains the selective response to beta-blockade?
- A)Beta blockers cross the blood-brain barrier and directly inhibit noradrenergic firing in the locus coeruleus
- B)Beta blockers enhance GABAergic neurotransmission in the prefrontal cortex
- C)Beta blockers prevent the peripheral sympathetic manifestations that reinforce cognitive anxiety through interoceptive feedbackGABARITO
- D)Beta blockers inhibit adrenocorticotropic hormone (ACTH) secretion, reducing cortisol-mediated anxiety
- E)Beta blockers block central nicotinic receptors on cholinergic neurons in the amygdala
Explicação
Beta blockers effectively reduce somatic/peripheral anxiety symptoms (palpitations, tremor, diaphoresis) because these receptors are abundant in the heart and skeletal muscle. By blocking β1 and β2 adrenergic receptors peripherally, propranolol reduces the phy... Ver explicação completa e trilha adaptativa →