Neuropharmacology Flashcards
What is substance dependance?
When an individual persists in use of alcohol/drugs despite problems related to the substance
What is substance abuse?
A maladaptive pattern of use of a substance that is not considered dependant
What is substance use disorder?
Substance abuse along with substance dependance
What is tolerance?
A person no longer responds to a drug. A higher drug doses are required to achieve the same effect
What is dependence?
A state in which a person functions normally only in the presence of a drug. There is physical or psychological disturbance when the drug is withdrawn
List some consequences of dependence
- Compulsive behaviour
- Loss of control in limiting intake
- Intense cravings even years after sobriety
What factors could pre-dispose you to having drug dependence?
- Genetics
- Personality
- Environment
- Pharmacokinetic properties of the drug
How is drug dependence associated with rationality?
Rationality is used to obtain goals but choosing our goals is often based on biological and social factors - not rationality. Drugs that cause dependence break down rationality. They chemically change our behaviour, values and feeling of “self”.
How do drugs cause addiction
Stimulation of the mesolimbic pathways. Dopamine release from VTA to the nucleus accumbens, pre frontal cortex, hippocampus and amygdala.
This results in euphoria, pleasure, motivation, compulsion.
Name some dependence inducing drugs and where they act.
Nucleus Accumbens (NAcc) - Cocaine, Amphetamine, Opiods, THC VTA - Ethanol, Nicotine, Opioids, THC
What biological changes occur during dependence?
- Upregulation of inhibitory autoreceptors in VTA
- Reduced dopamine release in NAcc
- Loss of inhibitory effect of D2 receptors with increased AC
- Supersensitivity of D1 receptors
- All leads to drug tolerence (drug is essential to maintain normal levels of pleasure)
What is (Delta)FosB?
A transcription factor that alters neural dendritic branches within the NAcc and the Prefrontal cortex. This leads to sensitised responses after repeat exposure to drug.
What are the two hypothesises of relapse in dependance?
- Structural change hypothesis
2. Behavioural change hypothesis
What types of drugs are used to treat Parkinson’s?
- Levodopa (Dopamine precursor) with peripheral decarboxylase inhibitor, Carbidopa / Benserazide
- Dopamine agonists - Ergot derivatives/Non-ergot derivatives/Non selective D agonist
- MAOb inhibitors
- COMT inhibitors
- Antimuscarinics
What are the Dopamine agonists that can be used in Parkinson’s?
- Ergot derivatives: Bromocriptine, lysuride, pergolide. Risk of pulmonary fibrosis in a small amount of patients
- Non-ergot derivatives: Ropinirole, rotigotine.
- Non-selective D agonist: (SC) Apomorphine.
What are the side effects of Dopamine agonists?
Vomiting (use Domperidone - peripheral D2 antagonist) Hallucinations Postural hypotension Sudden sleep onset Manic behaviour - gambling