Pharmacology CNS Flashcards
Which brain structures are primarily involved in Generalized Anxiety Disorder (GAD) as shown in neuroimaging studies?
The amygdala and the prefrontal cortex, with neuroimaging studies often showing decreased connectivity between these two areas in individuals with GAD.
What role does the neurotransmitter GABA play in GAD?
GABA is involved in inhibitory neurotransmission and helps to regulate anxiety. Dysregulation of GABA or GABA receptors has been observed in GAD patients, and GABA agonists can be effective in treatment.
How are serotonin and SSRIs related to GAD?
Serotonin, also known as 5-HT, is a neurotransmitter that is involved in the regulation of mood and anxiety. SSRIs, which increase serotonin levels, have been shown to be effective for the treatment of GAD.
What is the significance of the HPA axis in the neuroendocrinology of GAD?
The HPA axis regulates the stress response, and its overactivation can lead to the release of stress hormones like cortisol and adrenaline/noradrenaline, which are associated with the symptoms of GAD.
What have clinical trials revealed about corticotrophin-releasing factor (CRF) and neuropeptides in GAD treatment?
Clinical trials targeting corticotrophin-releasing factor (CRF) have been unsuccessful. GAD patients are hypersensitive to neuropeptides like cholecystokinin (CCK), but trials investigating CCK antagonists have also been unsuccessful.
How does genetics contribute to GAD ( General Anxiety Disorder)?
While the specific genes are not detailed in the provided material, genetics are believed to play a role in predisposing individuals to GAD, indicating that family history may be a risk factor.
What is a first class medicine for General Anxiety ? Give examples
SSRI (Selective Serotinin Reuptake Inhibitors)
Medicines such as
Sertaline
Paroxetine
Escitalopram
Increases levels of serotinin in the brain to regulate mood and reduce anxiety
What is a second line treatment for GAD?
SNRIs
Serotinin Norepinephrine Reuptake Inhibitors
E.g Duloxetine and Venlafaxine
Increase levels of serotinin and norepinephrine
Third line treatment for GAD
Antiepileptic Agent such as pregablin (lyrica)
Used if there is no respond to SSRI and SNRIs
It works by decreasing abnormal electrical activity in the brain, which can help to reduce anxiety.
Fourth line treatment for GAD ?
Benzodiazepines such as Alprazolam (Xanax)
Diazepam (Valium)
work by enhancing the effect of the neurotransmitter gamma-aminobutyric acid (GABA) in the brain.
How are benzodiazepines classified based on their duration of action?
Benzodiazepines are classified as short-acting (less than 5 hours), short-intermediate (5-24 hours), and long-acting (greater than 24 hours). This classification influences their clinical use, such as using short-acting types for sleep induction due to their rapid elimination.
Where do benzodiazepines bind on the GABA-A receptor?
Benzodiazepines bind to a specific site on the GABA-A receptor between the alpha (α) and gamma (γ) subunits.
What effect does the binding of benzodiazepines have on the GABA-A receptor?
Binding of benzodiazepines to the GABA-A receptor induces a conformational change that increases GABA’s ability to bind to the receptor, enhancing its inhibitory effect.
What happens when GABA binds to the GABA-A receptor in the presence of a benzodiazepine?
GABA binding in the presence of a benzodiazepine causes the chloride channel to open more frequently, leading to an increased flow of chloride ions into the neuron.
What is the result of the increased flow of chloride ions into the neuron?
The increased chloride ion flow hyperpolarizes the neuron, making it less likely to fire, resulting in the calming, anxiolytic effects of benzodiazepines.
How does hyperpolarization lead to the clinical effects of benzodiazepines?
Hyperpolarization inhibits neuronal activity, leading to a decrease in nervous system excitability, which manifests as sedation, reduced anxiety, muscle relaxation, and anticonvulsant effects.
Define seizure
a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.
Define Epilepsy
a pathologic and enduring tendency to have recurrent seizures.
Difference between seizure and epilepsy ?
seizure is a single event of abnormal electrical activity in the brain, while epilepsy is a disorder characterized by the repeated occurrence of seizures and encompasses a range of neurologic, cognitive, and social challenges.
Two main types of seizure
Generalized seizures (starts in both hemispheres)
Focal or partial seizures (starts in a focus then spreads)
Common generalized seizures
Typical absence
Myoclonic
Tonic clonic
Symptoms of generalized seizure, absence seizures ?
Mainly childhood in onset
Frequent brief attacks (1 – 30 s)
Sudden loss and return of consciousness
No aura and no post-ictal state
Some involuntary movements
Respond to some anti-epileptic drugs and not others
Explain the difference between a normal EEG and an absence seizure EEG
Normal EEG- The waves are relatively uniform and there’s no evidence of abnormal spikes or waves.
Absence seizure EEG- displays a very characteristic pattern known as a “3 Hz spike-and-wave” pattern. This pattern is repetitive and consists of a spike (a sharp upward deflection) followed by a slow wave (a dome-shaped upward deflection) represents the seizure activity.
Symptoms of generalized seizure- Myoclonus
Sudden, brief, shock-like muscle contractions Usually bilateral arm jerks
Often worse in the mornings
Precipitated by sleep deprivation and alcohol Define certain Epilepsy syndromes (e.g. JME) Respond to particular anti-epileptics
