Transmitters and Receptors Flashcards
How do drugs in the CNS interfere with chemical neurotransmission?
by affecting neurotransmitter: Synthesis, storage, release, inactivation (reuptake or metabolism) or receptor binding
What effect do Cocaine and Amphetamines have on the CNS? how do they do this?
increase NA in the synaptic cleft. Cocaine blocks reuptake of NA, whilst Amphetamines act directly on the storage vesicles and displaces NA
What are the main treatment options for epilepsy?
Reduce Excitatory input (Phenytoin) or Enhance inhibitory Input (Benzodiazepines)
How does Phenytoin work?
binds and inhibits intracellular portion of Na channels (channel has to be open to work) - blocking Na entry thereby decreasing excitatory fibre activity (ie less glutamate release?)
How do Benzodiazepines work?
Bind to the GABA A receptor at an allosteric site and enhances receptor infinity for GABA - which increases the frequency of the chloride channel opening. Increases the potency of GABA
What neurotransmitters are targeted for Anxiety?
Serotonin, NA, Neuropeptide Y
What neurotransmitters are targeted for Sedation?
Histamine
What neurotransmitters are targeted in the treatment of anxiety & sedation?
GABA, Serotonin
What are benzodiazepines used for?
Epilepsy, Anxiety, Sleep disorders, Premedication, Acute alcohol withdrawal
What drugs are used in the treatment of anxiety?
Benzodiazepines Beta-adrenoceptor antagonists Buspirone - partial agonist of 5HT1a receptor Zopiclone - bind GABA A receptor Zolpidem - bind GABA A receptor Barbiturates (in the past)
How do barbiturates work? what is their effect?
general depressants, bind GABA A receptor and increase the duration of Cl channel opening. Increases the efficacy of GABA
Which receptor do Benzodiazepines bind?
GABA A receptor
What kind of receptor is the GABA A receptor?
ligand-gated ion channel
What is the ligand and what is the ion involved in the GABA A receptor?
ligand = GABA, Ion = Cl
Why are benzodiazepines considered safer than barbiturates?
benzodiazepines are allosteric modulators so have a ceiling effect and do not increase the maximal response -> safer in overdose, whereas barbiturates act directly on the channel and increase the maximal response & no ceiling effect so in overdose can lead to coma and death
