bio lecture 5 Flashcards
What is pain?
A complex physiological and psychological experience.
What are nociceptors?
Specialized sensory receptors that detect pain and signal potential harm.
What happens when skin or organs get damaged?
Prostaglandins are produced, causing vasodilation and sensitizing free nerve endings.
What are the two types of nociceptors?
- Highly myelinated axons (Aδ fibres)
- Unmyelinated axons (C fibres)
What type of pain do Aδ fibres conduct?
Mechanical pain very quickly and precisely.
What type of pain do C fibres conduct?
Mechanical, heat, and chemical pain slowly and less precisely.
What is the role of the primary somatosensory cortex?
Processes pain sensation and indicates where the pain is located.
What is phantom limb pain?
Pain felt in a limb that has been amputated, suggesting the brain constructs pain experiences.
What are the two mechanisms of pain in the brain?
- Pain Sensation (physical) » Primary Somatosensory Cortex
- Unpleasantness perception » Anterior Cingulate Cortex
What is hypnosis-induced analgesia?
A non-drug approach that can reduce pain perception.
What does the placebo effect activate?
The dorsolateral prefrontal cortex, leading to pain suppression.
What is the role of the descending analgesia circuit?
Reduces pain by inhibiting pain signals from entering the CNS.
What are NSAIDs?
Non-Steroidal Anti-Inflammatory Drugs like aspirin and ibuprofen.
How do NSAIDs work?
Inhibit Cyclo-Oxygenase enzymes (COX-1 and COX-2), reducing prostaglandin production.
What is the mechanism of action for paracetamol?
Agonist to CB1 receptors and converts to AM404, affecting nociceptors.
What are opiates?
Drugs derived from the opium poppy or synthetically created for pain relief.
What are the three types of opioid receptors discovered in 1973?
- Delta
- Kappa
- Mu
What are the short-term effects of opiates?
- Pain relief
- Cough suppression
- Diarrhoea suppression
- Sedation
- Euphoria
What triggers the addictive potential of opiates?
They affect the Mesotelencephalic Dopamine System, increasing dopamine release.
What is cannabis derived from?
The Cannabis plant.
What are the active compounds in cannabis?
- THC (psychoactive)
- CBD (medicinal effects)
What are some short-term effects of recreational cannabis use?
- Reduced anxiety
- Distorted time perception
- Heightened sensations
What medicinal effects does cannabis have?
- Reduces nausea
- Increases appetite
- Decreases seizures
- Reduces pain
What negative effects can cannabis cause?
- Reduced motor coordination
- Intoxication similar to alcohol
Fill in the blank: Prostaglandins are produced in response to _______.
[tissue damage]
True or False: Pain is only a physical sensation.
False
What does the anterior cingulate cortex do?
Processes the unpleasantness perception of pain.
What is capsaicin used for?
Topical relief for muscle pain.
What does capsaicin trigger in nociceptors?
A pain response that depletes substance P from synapse.
What is naloxone?
An opiate receptor blocker that inhibits the effects of opiates.
How does acupuncture work?
Triggers activation of the descending analgesia circuit.
What are some therapeutic effects of cannabis?
Cannabis can reduce pain, ease glaucoma symptoms, and dilate bronchioles.
It is also noted to be as effective as opiates for pain relief.
What are the negative effects of cannabis use?
Negative effects include reduced motor coordination, slower reflexes, memory and attention impairments, paranoia, and panic attacks.
Intoxication effects can be similar to alcohol.
What is the origin and function of endogenous ligands?
Endogenous ligands are produced naturally within the body and bind to specific receptors to regulate physiological processes.
Examples include neurotransmitters like dopamine and hormones like insulin.
What distinguishes exogenous ligands from endogenous ligands?
Exogenous ligands are introduced from outside the body and can mimic, block, or alter the function of endogenous ligands.
Examples include drugs like morphine and toxins like nicotine.
What roles do THC and CBD play in cannabis?
THC acts as a partial CB1 and CB2 receptor agonist, while CBD serves as a CB1 antagonist that modulates THC effects.
The ratio of THC to CBD can influence the experience of the user.
Where are cannabinoid receptors primarily located?
CB1 receptors are mainly in the brain, and CB2 receptors are found in the immune system.
Cannabinoid receptors are also present in areas like the spinal cord and hypothalamus.
What are endocannabinoids and how do they function?
Endocannabinoids are neurotransmitters released from the postsynaptic cell that bind to receptors on the presynaptic cell, unlike traditional neurotransmitters.
This process occurs particularly at GABA-ergic synapses in the hippocampus.
What is ‘depolarization induced suppression of inhibition’?
It is a phenomenon in the hippocampus where endogenous cannabinoids released from postsynaptic neurons inhibit GABA release from presynaptic neurons.
This leads to increased neuronal depolarization and action potentials.
How does cannabis affect memory?
Cannabis use disrupts the natural patterns of neuronal activation, leading to memory problems and loss of memory formation.
This is due to cannabinoids stopping the release of neurotransmitters at synapses.
What are the long-term effects of cannabis use?
Long-term effects can include memory and attention impairment, slower decision-making, increased risk of psychosis, and IQ decline with early persistent use.
High-potency strains like ‘skunk’ are particularly associated with psychosis.
What is the legal classification of cannabis and opiates?
Opiates are classified as Class A drugs, while cannabis is classified as Class B.
This indicates that opiates carry higher legal consequences than cannabis.
How does THC affect psychological dependence?
THC increases dopamine release in the Nucleus Accumbens, contributing to psychological dependence.
Physical dependence on cannabis is considered low.
Fill in the blank: The two most common endogenous ligands for cannabinoid receptors are _______ and 2-AG.
Anandamide
True or False: Cannabis can cause overdose.
False
What is a unique case study involving an individual with a defect in the FAAH enzyme?
A 66-year-old woman required no post-surgical analgesia due to very high blood levels of anandamide, leading to a lack of pain sensation.
This case highlights the potential of targeting FAAH for pain treatment.
