An individual taking an SSRI antidepressant experiences increased serotonin levels in the synaptic cleft. Which effect dominates in the postsynaptic neuron due to this change?

💡 Explanation

SSRI antidepressants increase serotonin levels in the synaptic cleft by blocking its reuptake. Because the serotonin remains available for a longer duration, it prolongs activation of postsynaptic receptors, therefore the correct answer is prolonged receptor activation, rather than decreased action potential frequency from reduced stimulation.

• A patient with severe dehydration has impaired kidney function. Why does decreased glomerular filtration rate lead to oliguria (low urine output)?
• If a patient reports chronic pain despite opioid treatment following a spinal cord injury, which phenomenon explains the reduced analgesic effect via descending modulation?
• During hemorrhagic shock, why does increased sympathetic nervous system activity elevate blood pressure, often temporarily improving cardiac output?
• Why does aortic stenosis increase the risk of heart failure when the left ventricle's ejection fraction remains initially normal?
• Why does long-term potentiation strengthen synaptic connections during sleep?
• Why does mean arterial pressure (MAP) decrease significantly downstream from an arterial stenosis, even if cardiac output remains relatively constant?