5) Ions and Ach Ch 3,4 Julien and Wenk Ch3 Day 2

Agonists, Ions, and Action Potentials: Chapter 3 Summary

Overview: Topics cover agonists, receptors, neurotransmitter synthesis, ion role in brain signals, and action potentials.

Agonist Types:

• Full Agonist: Full response activation

• Partial Agonist: Weaker response (e.g., Buprenorphine)

  • treatment for people who want to get rid of opioid addiction

• Inverse Agonist: Reduces activity below baseline

Allosteric Modulators:

• Positive PAM: Enhances activation (e.g., Benzodiazepines)

• Negative NAM: Reduces responsiveness (e.g., Flumazenil)

Affinity:

• Higher affinity = stronger receptor binding and activation

Regulation:

• Down Regulation: Decreases receptors (e.g., tolerance)

• Up Regulation: Increases receptors, enhancing responses

Neuronal Properties:

• Resting potential ~ -70 mV maintained by sodium-potassium pump (3 Na+ out, 2 K+ in).

Neurotransmitter Synthesis:

• Dopamine from tyrosine hydroxylase; GABA from glutamine and glutamate.

Acetylcholine:

• Key role in CNS/PNS; linked to memory; affected in Alzheimer’s.

• Therapeutic: Acetylcholinesterase inhibitors improve cognition.

Clinical Implications:

• Effects of antagonists (e.g., Curare) and poison (e.g., Sarin) on muscle function highlight importance of Ach.

Key Takeaway: Understanding agonists, receptor activity, and neurotransmitter roles is vital in treating neurological disorders and grasping neuronal function.