Transmitters + Receptors (Benzodiazepine vs Barbituates)

Question 1

What is the difference btw Benzodiazepines & Barbituates?

• Mechanism
• PharmacoDynamics

Answer 1

BZD
“Allosteric Modulator” of GABA receptor
- Increased Freq of Cl ion Channel opening at GABA A receptor
- Increases Potency of GABA (PharmDyn)

Barbituates
“Direct opening of Cl channel” at GABA receptor
- Increase Duration of Cl channel opening at GABA A receptor (Prolong opening)
- Increase Efficacy of GABA
(PharmDyn)

Question 2

Why is there increased Toxicity in Barbituates?

Answer 2

• Direct Gating or Opening of Cl ion channel ( by Barbituate)
• Causes death in Overdose

Question 3

Do BZD bind GABA A or GABA B receptors?

- Describe each receptor type.

Answer 3

BZA only bind GABA A (Ligand gate Ion channel)

GABA B = G protein coupled receptor

Question 4

Define

• Potency
• Efficacy
• Orthostatic binding site
• Allosteric binding site

Answer 4

Potency = amt of drug, to give maximal effect
(only disadv. of Low potency = awkward to admininster very large dose

Efficacy= Strength of Receptor Activation
(ability of drug to do Right thing)

• Full Agonist = High Efficacy
• Partial Agonist = Low Efficacy