test 4 Flashcards
opioids, cannabis, and hallucinogens
what are the active ingredients in opium?
morphine and codeine
what is opium?
naturally occurring substance derived from poppy plants
what are the two ways by which opioids are derived?
-derived directly from opium
-synthetic drug with opium-like effect
what are the 3 opioid receptors?
-µ
-δ
-κ
which opioid receptors elicit which effects?
-most pharmacological effects are derived through activating µ and δ receptors
-κ receptors elicit hallucinogenic effects
how do opioids effect the medulla?
-neurons release endogenous opioids in the medulla, which contains a high density of µ opioid receptors
-reduces nociceptive information sent to the thalamus
describe the pain pathway
- C and Aδ neurons send nociceptive (pain stimuli) information from environment to the spinal cord
-causes a release of glutamate and substance P neurons in the spinothalamic pathway
-then sends nociceptive information to thalamus, then to the somatosensory cortex (where information is processed) and the cingulate cortex (approach/avoid behavior) and amygdala (emotional response) in the limbic system
how do opioids effect the pain pathway?
-reduce glutamate and substance P (stops in the spinal cord)
-still get sensory pain but not the perception of it
what are the withdrawal symptoms of opioid use and what acute pharmacological effect is each caused by (7)?
-pain sensitivity (analgesia)
-diarrhea (constipation)
-increased blood pressure (decreased blood pressure)
-dysphoria and depression (euphoria)
-hyperthermia (hypothermia)
-restlessness (relaxation)
-hyperventilation (respiratory depression)
what are the medical uses for opioids?
-morphine and other opioid analgesics (lack significant efficacy for neuropathic (damage to nociceptive neurons) and idiopathic (pain from an unknown source) pain
-diarrhea
suppress cough reflex
how do opioids help diarrhea?
-inhibitory effects of opioid receptors in the intestinal tract
how do opioids help suppress cough reflex? what are some examples of medications?
-activate inhibitory opioid receptors
-codeine is a prescription cough syrup
-dextromethorphan in OTC medications
what are the differences between heroin and morphine?
-heroin has high lipid solubility, so it can pass the blood-brain barrier easier while morphine has poor lipid solubility
-morphine has gradual onset effects while the onset effects of heroin are rapid
what is the antagonist treatment for opioid dependence? what are two examples? Describe each.
-increased severity of withdrawal symptoms but shortened duration
-naloxone- short-acting opioid antagonist
-naltrexone- long-acting opioid antagonist and has shown to be effective but only for highly motivated individuals
what is the controlled schedule listing for marijuana?
schedule III
describe the lipid solubility of cannabis
-Δ9-THC exhibits high lipid solubility
-leads to rapid distribution into tissues, including the brain, and accumulation in fat
-Δ9-THC in fat releases slowly over time which leads to long-term pharmacological actions and long elimination rates
what are the 2 endocannabinoids?
-anandamide
-2-AG
what are the two cannabinoid receptors?
-CB1
-CB2
what are CB1 receptors?
-found throughout the brain
-Δ9-THC and anandamide have high affinity
-2-AG has weak affinity
-dense population in the eye
-leads to increased dopamine concentration in the nucleus accumbens
what are CB2 receptors?
-density found in the immune system
-exhibit inhibitory effects
describe how cannabis can cause a sense of accelerated time
-related to a reduction of activity in the cerebellum which can cause slower cognitive processing and sensory integration
explain the relationship between cannabis and lung cancer.
- cannabis smoke contains more carcinogens than tobacco cigarettes which results in a greater amount of tar in the lungs, but it contains chemicals that may limit a user’s risk of lung cancer and other cancers
-studies fail to show a relationship between cannabis and lung cancer, but they have found that cannabis can increase the risk of respiratory diseases like bronchitis and emphysema
what is dronabinol?
- oral Δ9-THC preparation
-1985- FDA-approved for sale to cancer patients experiencing nausea from chemotherapy as an antiemetic
1993- FDA approved for sale to AIDS and cancer patients to stimulate appetite
what are the arguments for making smokable medical marijuana legal?
-rapid onset
-greater ability of the patient to control effects
-other ingredients in marijuana plant may be beneficial and limit negative subjective or other behavioral effects of Δ9-THC
what is the active ingredient in shrooms?
psilocybin
what is the difference between indole and catechol hallucinogens?
-indole hallucinogens have similar chemical structure to serotonin and catechol hallucinogens share a similar chemical structure to norepinephrine and dopamine
-indole hallucinogens alter sensory perception while catechol hallucinogens do the same but also have stimulant-like effects
what are examples of indole hallucinogens? what is an example of a catechol hallucinogen?
-LSD, psilocybin
-MDMA
what are the mechanisms of action for indole hallucinogens?
-5-HT1A and 5-HT2A agonist
-effects sensory-processing systems by interfering with modal object completion in the visual cortex
what are the mechanisms of action of MDMA?
-similar to amphetamines
-MDMA increases 5-HT levels which inhibits storage in vesicles and inhibits reuptake
-to a lesser extent dopamine levels increase via same mechanisms
how does LSD effect glutamate?
-increases the activity of glutamate which enhances sensory signals to the cerebral cortex and increases activity in the prefrontal cortex
describe the physiological effects of LSD
-mild physiological effects
-modest changes in heart rate, slight dizziness, and mild nausea
describe the subjective effects of LSD
-strong subjective experiences
-true hallucinations are rare
-pseudo-hallucinations, altered perception of things that are real, are common
-synesthesia
what is synesthesia? what is an explanation for synesthesia? what is some evidence?
-experiencing sensory stimuli in an incorrect sensory modality
-affects the temporo-parietal-occipital junction which lacks proper inhibitor feedback which leads to additional perceptions to a single stimulus; there is an activation of 5-HT2A receptors
-produced by LSD; inhibited by SSRIs where an activation of 5-HT1A reduces 5-HT2A making individuals less likely to experience synesthesia; inhibited by SNRIs by the activation of the α2 adrenoceptors which reduces 5-HT2A making individuals less likely to experience synesthesia
what is rebound?
-occurs 24 hours after the use of MDMA
-consists of depression and lethargy
-MDMA temporarily depletes serotonin and dopamine stores
-replenishing these stores can take several days
describe opioid’s effects on reward circuitry
-produce reinforcing effects by affecting dopamine and GABA neurotransmission
-opioids bind to μ receptors on GABA neurons in the VTA and the nucleus accumbens
an increase in opioids causes a decreases in GABA which then leads to an increase of dopamine being sent from the nucleus accumbens to the VTA
what is the training for conditioned place preference experiments?
-there are two boxes that environmentally differ so subjective effets can be paired with environmental cues
-the rat is given a drug in one environment
-the NS (room) is paired with the US (drug) to produce a UR (subjective effects) and the rat then pairs the room with the subjective effects
-do the same in the other environment with the saline for a control and the other room
what is the testing for condition place preference experiments?
-rat gets free range of the two compartments
-test to see if the rat would rather spend its time in a place where it felt subjective effects
-a drug has more reinforcing effects if the rat spends more time in the room it associates with the drug’s subjective effects
describe the study done by Siegel et al. (1982)
-rats were injected with heroin in two different environments
-at the end of each month, the rats tolerated 8.041 mg/kg of heroin
-half were then moved from their compartment and all the rats got double the initial dose
-twice as many rats in the new environment died from overdose
-the conditioned response the rats developed in the controlled environment allowed rats to tolerate the high drug dose because of the compensatory response
what are the medical uses for marijuana? describe at least 2.
-pain- shown to alleviate neuropathic pain because there are CB1 receptors in the thalamus, brain stem, spinal cord, and cerebral cortex that help inhibit pain
-glaucoma (damage to the optic nerve due to fluid buildup)- activating the CB1 receptors reduces eye pressure
-autoimmune diseases- suppressed immune system response but may also enhance the risk of infection
-antiemetic- help cancer patients going through chemotherapy
-used to stimulate appetite for AIDs and cancer patients
describe the relationship between PCP and schizophrenia
-it has cataleptic-like effects because it is an acetylcholine antagonist, meaning that muscle movements will be decreased
-PCP can cause schizophrenia-like effects like hallucinations and disorganized thinking and can last for days, even weeks after drug administration
-according to the glutamate hypothesis of schizophrenia, symptoms occur because of decreased glutamate transmission
how does LSD effect GABA?
-increased GABA release decreases activity in the locus coeruleus which causes greater refinement of sensory signals to the cerebral cortex leading to normally suppressed sensory information from the locus coeruleus becoming more refined and salient
