Cannabis Flashcards
What are endocannabinoids?
Endogenous neurotransmitters that stimulate CB1 and 2 receptors.
What kind of receptors are CB1 and CB2 and where are they found?
Pre-synaptic GPCRs: CB1 is found in the CNS and CB2 in the PNS.
What are endocannabinoids involved in? List 4 things.
- Pain
- Mood
- Memory
- Appetite
Describe the transmission of endocannabinoids.
Retrograde transmission: they are released by the post-synaptic neuron and act on the pre-synaptic neuron.
What affect do endocannabinoids have on the pre-synaptic neuron?
They reduce the amount of neurotransmitter released
How do endocannabinoids reduce the amount of neurotransmitter released by the pre-synaptic neuron?
Cannabinoid binding to the CB1 receptor causes an inhibition of adenylate cyclase. This causes a reduction in the production of cAMP, which means reduced activation of PKA. This affects K+ and Ca2+ channels, i.e. it is harder to generate APs and release NTs.
What is arguably the most prevalent endocannabinoid?
Anandamide.
Endocannabinoids are hydrophilic. True or false?
False: they are extremely lipophilic and stick to cell membranes.
Cannabis is a class B drug. True or false?
True.
Cannabis falls into the depressant category, although it is a weak depressant. What is a depressant?
A drug that affect inhibitory neurotransmission.
What is the active ingredient in cannabis?
THC or delta-9-tetrahyrdocannabinoid.
THC is a synthetic chemical. True or false?
False: it is naturally occurring in cannabis plants.
Cannabis only comes in one form and is always the same strength. True or false?
False: it comes in multiple forms that vary in strength, e.g. resins, leaves etc.
What does THC do in the body?
It binds the CB1 receptor as it is structurally similar to endocannabinoids. This is competitive inhibition.
How does THC affect inhibitory neurotransmission?
GABA neurons have CB1 receptors, thus THC binds these and reduces the release of GABA.
What effect does reduced GABA transmission have on dopamine?
It increases the release of dopamine: normally GABAergic neurons inhibit dopamine release. When GABA is inactivated by THC dopaminergic neurons become more active than normal.
What does increased dopamine create?
A increased sense of reward: dopamine released by the VTA causes dopamine release in the nucleus accumbens, this is the brain’s reward pathway.
List 8 effects of cannabis.
- Slight euphoria
- Relaxation
- Amplified sensory perception
- Inhibited balance and motor activity
- Munchies
- Nausea/vomiting
- Anxiety and paranoia
- Confused temporal memory
How does cannabis produce euphoria?
Due to its effects in the reward pathway.
The amplified sensory perceptions attributed to cannabis use can be mildly hallucinogenic. Why is this?
Increased dopamine is associated with psychosis, e.g. the positive symptoms of schizophrenia.
Which sensory perceptions are amplified the most by cannabis?
Sound, smell, taste and touch.
Which areas of the brain are affected by cannabis to produce the motor inhibition?
The basal ganglia and cerebellum.
Why can cannabis make you nauseous and vomit?
Dopamine controls the CTZ or chemoreceptor trigger zone that controls nausea and vomiting.
Which areas of the brain are affected to produce anxiety/paranoia and memory deficits?
The hippocampus.
How long do the effects of cannabis last?
~3hours.
How long is cannabis traceable in the body for?
~2weeks.
Why is prolonged cannabis usage thought to decrease attention, learning/memory and cognitive abilities?
The CB1 receptors in the brain arteries become sensitised to cannabinoids and thus become non-functional. This can cause a reduction in blood flow to the brain, resulting in less oxygen and glucose for brain cells.
Does cannabis cause amotivation?
It is not clear whether cannabis is a causal factor or an accompaniment to a lazy lifestyle.
Does cannabis cause psychosis?
It may increase the risk in those that are already predisposed. For example dopamine over-activity is thought to be behind the positive symptoms of schizophrenia, plus the loss of CB1 receptors in the brai arteries appear to induce symptoms of cognitive schizophrenia.
List 3 therapeutic uses of cannabis?
- Antiemetic
- Cancer pain
- Parkinson’s and MS
Why is cannabis useful as an antiemetic?
It affects dopamine levels and dopamine regulates the CTZ.
Why is cannabis not regularly used as an antiemetic?
Because the withdrawal and side effects are unpleasant.
What kind of benefits does cannabis give cancer patients? List 6.
- Analgesia
- Increased appetite
- Mood elevation
- Sedation
- Amnesia
- Muscle relaxation
Why might cannabis be useful for Parkinson’s and MS?
It provides muscle relaxation that counteracts spasticity.
How does cannabis provide analgesia?
It activates inhibitory Mu receptors, thus diminishing the pain response.
