Answer: Acting as positive allosteric modulators of GABA-A receptors, increasing frequency of Cl- channel opening in response to GABA.
- A Directly and competitively blocking GABA-A receptors, thereby reducing inhibitory chloride conductance levels as widely reported
- B Acting as positive allosteric modulators of GABA-A receptors, increasing frequency of Cl- channel opening in response to GABA
- C Mimicking the action of glutamate at excitatory NMDA and AMPA receptor binding sites directly in standard practice under most conditions encountered
- D Blocking voltage-gated sodium channels distributed along the entire length of the axon membrane as frequently observed in practice
Correct answer: B. Acting as positive allosteric modulators of GABA-A receptors, increasing frequency of Cl- channel opening in response to GABA
Explanation: Benzodiazepines bind allosteric site on GABA-A receptors. In presence of GABA, they increase channel opening frequency. More Cl- influx → greater hyperpolarization → anxiolysis, sedation.
Structure of a neuron. Image: LadyofHats (Mariana Ruiz), Public Domain, via Wikimedia Commons.
Concept context
Brain, spinal cord, neurons, reflex arcs, and sense organs.