Behavioral Neuroscience M4

What is a Drug?

  • Definition:

    • "An exogenous chemical not necessary for normal cellular functioning that significantly alters the functions of certain cells of the body when taken in relatively low doses."

    • Focus on cells within the nervous system.

  • Drug effects and sites of action.

Overview of Pharmacology

  • Pharmacology: Study of all drugs.

  • Psychopharmacology: Study of drugs that affect the nervous system and behavior.

    • Categories of drugs:

      • Drugs of Abuse: Heroin, cocaine.

      • Therapeutic Drugs: Antidepressants, antibiotics, antihypertensives.

Page 5: Pharmacokinetics

  • Definition: The life cycle of a drug molecule.

  • Stages of pharmacokinetics:

    • Absorption: Drug is administered and absorbed throughout the body.

    • Distribution: Drug is distributed through tissues (e.g., intramuscular injection).

    • Metabolism: Drug is changed to an inactive form by liver enzymes.

    • Excretion: Drug is excreted in urine by kidneys.

Page 6: Pharmacokinetics - Routes of Administration

  • Intravenous (IV) Injection: Fastest route.

  • Other routes include:

    • Intraperitoneal (IP) injection.

    • Intramuscular (IM) injection.

    • Subcutaneous (SC) injection.

    • Oral administration (most common).

    • Sublingual administration.

    • Inhalation.

    • Insufflation (sniffing/snorting).

    • Topical administration.

    • Intracerebral/intracerebroventricular administration.

Page 7: Cocaine in Blood Plasma - Absorption

  • Graph depicting absorption of cocaine in different routes:

    • Intravenous (0.6 mg/kg)

    • Smoked (100 mg base)

    • Oral (2 mg/kg)

    • Intranasal (2 mg/kg)

    • Time on X-axis (minutes) and plasma levels on Y-axis (mg).

Page 8: Lipid Solubility of Drugs

  • Comparison of two drugs:

    • Heroin: More lipid soluble.

    • Morphine: Less lipid soluble.

Page 9: Drug Effectiveness

  • Dose-Response Curve

    • Describes the relationship between drug dose and effect.

    • After a certain dose, increasing the amount does not produce a stronger effect.

Page 10: Therapeutic Index

  • Measures the safety margin of a drug:

    • Therapeutic Index = Toxic Dose / Therapeutic Dose.

    • A larger index indicates a safer drug.

Page 11: Variability in Drug Effectiveness

  • Factors affecting drug effectiveness:

    • Sites of action.

    • Affinity of a drug with its site of action.

  • Key goal: High margin of safety and high therapeutic effects along with low toxic side effects.

Page 12: Effects of Repeated Administration

  • Tolerance: Decrease in effectiveness of a drug over time.

  • Sensitization: Increase in drug effects with repeated use.

  • Withdrawal Symptoms: Indicate physical dependence and adjustments in homeostasis.

    • Compensatory mechanisms modify receptor sensitivity and numbers, affecting binding effectiveness.

Page 13: Placebo Effects

  • Discussion on placebo effects in pharmacology.

Page 14: Synaptic Transmission Overview

  • Introduction to the process of signal transmission between neurons.

Page 15: Electrical Synapses

  • Description of Electrical Synapses:

    • Ions pass freely between cells.

    • Gap Junctions are less common in psychopharmacology.

Page 16: Chemical Synapses

  • Types of synapses:

    • Axodendritic synapses: Between axon and dendrites.

    • Axoaxonic synapse: Between two axons.

Page 17: Synaptic Transmission Mechanism

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