Quiz 3 BNA wk 8

• Neurochemistry


  Focuses on the basic chemical composition and processes of the nervous system
• Neuropharmacology


  The study of compounds that selectively affect the nervous system
• Binding affinity and drug effectiveness

  • Receptor regulation
  • Drugs effect on presynaptic mechanisms
  • Drug effects on postsynaptic mechanisms
• Typical antipsychotics


  Selective dopamine D2 antagonists (reduce positive symptoms of schizophrenia, such as delusions and hallucinations)
• Atypical antipsychotics


  Typically block some serotonin receptors and seem to reduce negative symptoms (such as social withdrawal and blunted emotional responses) of schizophrenia
• Third generation antipsychotics


  Target novel synapses such as glutamate
• Monamine oxidase (MAO) inhibitors

  Prevent the breakdown of monoamines at the synapse
• Tricyclic antidepressants


  Increase norepinephrine and serotonin at the synapses by blocking their reuptake into presynaptic axon terminals
• Selective serotonin reuptake inhibitors (SSRIs)


  Allow serotonin to accumulate in the synapses, with fewer side effects than tricyclics
• Anxiolytics or tranquilizers


  Depressant drugs that reduce nervous system activity
• Benzodiazepine agonists


  Act on GABAa receptors and enhance the inhibitory effects of GABA
• Allopregnanolone


  A steroid that is elevated during stress and is calming
• Neurosteroids


  Steroids produced in the brain that may act on GABAa sites
• Designer receptors exclusively activated by designer drugs (DREADDs)

  Receptors engineered to respond to synthetic ligands
• Opium


  Extracted from poppy seeds, contains morphine, an effective analgesic or painkiller
• Morphine and heroin


  Related and highly addictive opiates that bind to opiate receptors in the brain
• Endogenous opiates


  Peptides produced in the body that bind to opioid receptors and relieve pain
• Types of endogenous opiates

  • Enkephalins
  • Endorphins
  • Dynorphins
• Opiate receptors


  Three main types: Delta δ, Kappa κ, Mu μ (all are metabotropic)
• Δ9-tetrahydrocannabinol (THC)


  The active ingredient in marijuana, with effects including relaxation, mood alteration, stimulation, hallucination and paranoia
• Cannabinoid receptors


  Concentrated in the substantia nigra, hippocampus, cerebellar cortex and cerebral cortex
• Types of cannabinoid receptors

  • CB1 (only in CNS, mediates rewarding properties)
  • CB2 (prominent in immune system)
• Endocannabinoids


  Homologs of marijuana produced in the brain, act as retrograde messengers and may influence neurotransmitter release
• Anandamide


  An endocannabinoid with effects including altering memory formation, stimulating appetite, reducing pain sensitivity, protecting from excitotoxic brain damage, lowering blood pressure, combating nausea, and lowering eye pressure from glaucoma
• Chronic or heavy marijuana use has negative effects including transient amnesia, stimulation and paranoia, respiratory problems, addiction, cognitive decline, and psychiatric disorders
• Stimulants


  Increase nervous system activity and have an alerting activating effect
• Nicotine


  Acts as an agonist on nicotinic ACh receptors in the body and brain, with rewarding effects mediated by receptors in the ventral tegmental area
• Cocaine


  Blocks monoamine transporters, especially dopamine, slowing reuptake of neurotransmitters and enhancing their effects
• Cocaethylene


  An active metabolite formed when cocaine is metabolised in the presence of ethanol, to which the user may develop an additional addiction
• Amphetamine and methamphetamine


  Synthetic stimulants that resemble catecholamine transmitters in structure, causing the release of neurotransmitters even in the absence of action potentials and potentiating release with action potentials
• Dual dependence


  Addiction to the effects of the interaction of 2 drugs
• Dual dependence


  • Cocaine metabolised in presence of ethanol (alcohol) yields an active metabolite called cocaethylene to which the user may develop an additional addiction
• Cocaine binding sites in the brain


  • Shown in image
• Amphetamine and methamphetamine


  Synthetic stimulants that resemble catecholamine transmitters (norepinephrine, epinephrine and dopamine) in structure
• How amphetamine enhances activity

  1. Causes release of neurotransmitters even in the absence of action potentials

  2. Potentiates release with action potentials

  3. Blocks the reuptake of catecholamines into the presynaptic terminal

  4. Provides an alternative target for the enzyme (monoamine oxidase) that normally inactivates catecholamines
• Short term effects of amphetamines

  • Alertness, euphoria and stamina
• Long term effects of amphetamines

  • Sleeplessness, weight loss and general deterioration of mental and physical condition
• Prolonged use of amphetamine

  • May lead to symptoms that closely resemble those of paranoid schizophrenia: compulsive, agitated behaviour and irrational suspiciousness
• Alcohol's effects


  Biphasic - an initial stimulant phase followed by a depressant phase
• How alcohol affects the brain

  1. Activates GABAa receptors and increases inhibitory effects

  2. Stimulates dopamine pathways, causing euphoric effects