Final Neuro Study Guide 4

Alcohol
- Ethanol as a metabolic product of yeast
- Ethanol vs methanol vs isopropanol as it relates to toxicity
- Ethanol absorption in stomach and intestinal tract, effect on blood alcohol content
of consuming with or without food.
- Liver metabolism of ethanol general understanding that enzymes break down
ethanol in the liver and what effects blocking these enzymes (genetically or
pharmacologically have on ethanol metabolism and physiology.
- Sex differences in alcohol bioavailability.
- Types of tolerance related to acute and chronic ethanol consumption
- Ethanol enhances the activity of GABA receptors
- Chronic ethanol exposure leads to downregulation of GABA receptors— acute
withdrawal therefore can lead to seizures- Disruptions in the excitatory/inhibitory
balance
Anesthesia
- Difference/positives vs. negatives between Local, Regional, General anesthesia
- General anesthesia- unconsciousness, analgesia, amnesia, akinesia
- The discovery of curare and its importance as a paralytic during surgery- effects
on nicotinic acetylcholine receptors
- Discovery of inhaled anesthetics- nitrous oxide in oral surgery and the ether
dome in Mass General!
- Theories of the mechanism of action of inhaled general anesthetics: Meyer-
Overton hypothesis (i.e. membrane/lipid hypothesis) vs. protein hypothesis
(direct interaction with membrane proteins- GABA receptors being a major target)
- Minimum alveolar concentration as it relates to potency, ED50, and age of a
person
- Therapeutic range vs. therapeutic index. How we calculate therapeutic index
Serotonin/Hallucinogens/Antidepressants

### Alcohol - **Ethanol as a Metabolic Product of Yeast**: Ethanol is produced during fermentation by yeast as they metabolize sugars in anaerobic conditions. - **Toxicity Comparison**: Ethanol, methanol, and isopropanol differ significantly in toxicity. Ethanol is relatively safe in moderation, while methanol and isopropanol are highly toxic and can cause severe health issues. - **Absorption and Blood Alcohol Content**: Ethanol is absorbed in the stomach and small intestine; consuming alcohol with food slows down absorption, which affects blood alcohol content (BAC). - **Liver Metabolism**: Ethanol is metabolized in the liver by enzymes; blocking these enzymes, whether genetically or through medication, can affect how ethanol is processed and its physiological effects. - **Sex Differences in Alcohol Bioavailability**: Women typically have a higher blood alcohol concentration than men after consuming the same amount of alcohol due to physiological differences. - **Types of Tolerance**: There are two main types of tolerance to ethanol: acute tolerance (short-term) and chronic tolerance (long-term use). - **Ethanol and GABA**: Ethanol enhances the activity of GABA receptors, which are responsible for inhibitory neurotransmission in the brain. Chronic exposure leads to downregulation of these receptors, increasing susceptibility to seizures during withdrawal due to disrupted excitatory/inhibitory balance. ### Anesthesia - **Types of Anesthesia**: Local anesthesia numbs a specific area, regional anesthesia blocks sensation in larger areas, and general anesthesia induces unconsciousness, analgesia, amnesia, and akinesia. - **Curare Discovery**: Curare was identified as an important paralytic agent during surgeries, affecting nicotinic acetylcholine receptors and leading to temporary paralysis. - **Inhaled Anesthetics**: The development of nitrous oxide for oral surgery and the ether dome at Massachusetts General Hospital marked significant milestones in anesthetic practices. - **Mechanism of Action Theories**: The Meyer-Overton hypothesis suggests that anesthetic potency correlates with lipid solubility, while the protein hypothesis posits that inhaled anesthetics exert their effects through direct interaction with specific proteins like GABA receptors. - **Minimum Alveolar Concentration**: This is a measure of anesthetic potency, indicating the concentration needed to prevent movement in response to surgical stimuli in 50% of patients. - **Therapeutic Range vs. Therapeutic Index**: The therapeutic range indicates the dosages of anesthetics that are effective, while the therapeutic index is the ratio of toxic dose to effective dose, crucial for safety in anesthesia practice.