Transmitters and Receptors Flashcards
in order to effect the CNS, drugs must be able to cross the [….]. after which they may be go on to modulate NT synthesis, [….], release, [….], or receptor.
BBB
inactivation (reuptake, metabolism), storage
a depolarization event and Calcium++ release cause the release of NA into the synaptic space. From here it is either metabolized by […] on the prejunctional membrane, go through reuptake channels to be metabolized by intracellular [….], bind […..] receptors on the postjunctional membrane, and/or undergo postjunctional reuptake via postjunctional channels.
alpha receptors
MAO
alpha/beta NA
cocaine blocks neuronal [….], causing NA to become […..].
reuptake of NA
depleted
how is phenytoin optimized to be optimally active only during epileptic fits?
phenytoin decreases excitatory fibre activity, decreases glutamate release on post synaptic motor nerve fibre by inhibiting Na+ channels, but only when the sodium channel is open (during an epileptic event).
as a Tx for epilepsy, benzodiazapines act to enhance inhibitory […] NT activity, thereby inhibiting motor nerve stimulation.
GABA
what NT’s are targeted in drugs treating sedation & anxiety? Associated receptors?
GABA –> GABA A ligand-gated receptor.
Histamine is targeted to produce sedation in paediatric patients via H1 receptor anatagonists.
what NT’s are targeted in drugs treating anxiety? Associated receptors?
Serotonin targeted on CNS pre-junctional receptors.
Noradrenaline to treat peripheral tachycardia.
Neuropeptide Y –> NPY1 receptor reduces anxiety
beta-adrenoreceptor antagonists block the physical signs of [….] (sweating, tremor, tachycardia), however they have little effect on the [….], or the root cause of the problem.
anxiety
CNS
clinically recognized anxiety disorders are: generalized anxiety states, [….], […], and post-traumatic stress disorder.
They can be treated with anxiolytics, but these also have the effect of causing […] and […].
panic disorder
phobia
drowsiness
sedation.
Anxiolytic agents are:
1. benzodiazepines - treating anxiety states and insomnia.
- non benzodiazepines - […..] antagonists, treat peripheral symptoms of anxiety
- [……]
beta adrenoreceptor
barbiturates - used in controlled settings only as anticonvulsants/anaesthesia. too toxic for general anxiety
benzodiazepines have a […] therapeutic index.
they act to reduce [….] and anxiety, elicit sedation and [….], and obliterate [….]
wide.
muscle tone.
induction of sleep.
memory.
GABA is the main inhibitor NT in the CNS. It has two type of receptors:
- GABA […] receptors are [….] channels
- GABA […] receptors are […..] receptors.
Benzodiazepines only interact with the […] receptor only, and act to increase the receptors affinity for […..].
GABA A - ligand gated ion
GABA B- G-protein coupled
GABA A
GABA
Benzodiazepines only interact with the […] receptor, and act to increase the receptors affinity for […..] by binding to an […] site. In this sense, they are [….] modulators.
This increases the frequency of […..], without changing the […..].
NB: This effectively increases the sensitivity of the channel without increasing the maximum response.
GABA A
GABA
orthosteric site.
orthosteric.
the GABA A Cl- channel opening.
mean conductance or channel open time
As opposed to benzodiazepines, the barbiturates bind the GABA receptor and act to [….], increasing the sensitivity AND maximum response of the channel.
prolong channel opening time.
–>Barbiturates will kill you! Benzo’s won’t!
short-acting benzodiazepines are [….] and […]. These are ideal for use as [….].
They cause no daytime […] and safe for use in the elderly and drivers.
Disadvantages?
oxazepam and temazepam.
hypnotics.(tx insomnia)
anxiety.
Disadvantages:
As an anxiolytic they are slow-onset and require fine dosing control, 3-4 doses per day is required.
