Lecture Notes Review - Psychopharmacology and Neurotransmitters

Announcements

  • Research Participation:

    • Target Group: 1st generation immigrant students.
    • Objective: Interview about student experiences to improve psychosocial supports in higher education.
    • Criteria: Permanent residents in Canada (including refugees), immigrated after age 12, completed at least one semester at Bishop’s, and lived in Canada for at least one year.
    • Interview Duration: Approximately 1 hour.
    • Contact Person: Claude Charpentier (ccharpen@ubishops.ca).

  • Clinical Case Study Challenge (BUUPS):

    • Date and Time: March 11th, 2025, from 6:00 PM to 9:00 PM.
    • Location: Adams Dining Room (Dewhurst).
    • Event Highlights:
    • Teams of four create a case study based on a given diagnosis.
    • Evaluation by a panel of three judges.
    • Public invited to attend the second half of the event.
    • Registration: Required.

Psychopharmacology

  • Key Terms:

    • Affinity: Strength of binding between a ligand and its receptor.
    • Efficacy: Effectiveness of the ligand in activating the receptor.
    • Agonist vs. Antagonist:
    • Agonist: activates the receptor.
    • Antagonist: blocks the receptor.

  • Neurotransmitter Functions:

    • Each neurotransmitter is associated with specific behaviors, has unique synthesis pathways, and interacts with distinct receptors.
    • Different routes of drug administration impact the speed and effectiveness of drug action.

  • Pharmacokinetics vs. Pharmacodynamics:

    • Pharmacokinetics: Drug movement within the body (absorption, distribution, metabolism, excretion).
    • Pharmacodynamics: Effects of drugs on the body after absorption, particularly at receptor sites.

Pharmacodynamics

  • Factors Influencing Drug Effects:

    • Site of Action: Receptor locations determine physiological and behavioral effects.
    • Affinity: Binding strength and duration of a ligand to its receptor.
    • Efficacy: How effectively a bound ligand alters the receptor's activity.

  • Lock and Key Model:

    • Describes how ligands bind to receptors, enabling physiochemical changes in the target cell.

Drug Mechanisms of Action

  • Stages of Drug Interaction:
    • Synthesis, Storage, Release, Receptor Interaction, Inactivation, Reuptake, and Degradation of neurotransmitters.

Neurotransmitters Overview

  • Acetylcholine (ACh):

    • Involved in all muscle movements (somatic nervous system) and autonomic functions (both sympathetic and parasympathetic).
    • Degradation by acetylcholinesterase leads to recycling of choline and acetate.

  • Catecholamines (Dopamine, Norepinephrine, Epinephrine):

    • Involved in arousal and motivational behaviors; synthesized in series from the precursor during stress responses.

  • Dopamine (DA):

    • Functions in movement control and reward pathways; pathway disruptions can lead to disorders like Parkinson's Disease.

  • Norepinephrine (NE):

    • Derives from the locus coeruleus, influences autonomic processing and arousal.

  • Serotonin (5-HT):

    • Derives from tryptophan, key in mood, learning, and sleep regulation with multiple receptor subtypes.

Amino Acid Neurotransmitters

  • Glutamate:

    • Most abundant excitatory neurotransmitter in the CNS; crucial for learning and memory processes.
    • Involved in synaptic plasticity, implicated in neurotoxicity under excessive stimulation.

  • GABA (Gamma-Aminobutyric Acid):

    • Primary inhibitory neurotransmitter, key for controlling neuronal excitability throughout the nervous system.
    • Comes in two receptor types (ionotropic and metabotropic), mediating various physiological responses via chloride and potassium channels.