Question

Lorazepam is a positive allosteric modulator with high affinity for GABAA receptors, membrane bound, ligand-gated channel permeable to chloride. Answer the following questions regarding the administration of lorazepam for the patient in this case study.

a. Identify two membrane-bound proteins present that significantly influence the resting membrane potential of an excitable cell. For each, identify the ions transported and the type of membrane transport (active/passive).

b. Describe how membrane-bound ligand-gated channels transiently alter membrane permeability to a particular ion, and identify the type of membrane transport (active/passive).

c. Justify the administration of lorazepam for the patient’s tonic-clonic seizures. Be sure to state how lorazepam will impact the resting membrane potential, graded potentials, and action potentials in a neuron. Be sure to reference at least one equation in your explanation, and state why the drug would be beneficial for the patient.

Answer 1

a) Na-K ATPase pump,ligand voltage gated K channels.The pump allows exit of 3 Na ions and entry of 2 K ions by active transport.The channels allow transport via the concentrtation gradient by passive transport.

b)In the presewnce of a chemical messenger,the ligand gated channels open and thus allow entry or exit of ions.This occurs by passive transport.

c)Lorazepam has high affinity for GABA receptors and thus creates an inhibitory potential which may help in patient's with seizures.They also bind with the voltage gated Na channels inhibiting the repeated firing.

Lorazepam increases the frequency of opening of cl channels on the GABA receptors and thus creates a inhibitory potential which is due to repolarisation of the resting membrane potential.