2.1 Pharm receptors Flashcards
Neuronal excitability or ihibition depends on
the flux of ions through specific channls in neuronal membrans
excitation via membrane depolarisation
inc Na in or
dec K out
inhibition via membrane hyperpolarization
inc Cl in or
inc K out
2 major types of ion channels
voltage gated, NT gated
voltage gated channels are regulated by
membrane potentials
examples of voltage gated channels
na channels in axonal conduction, ca channels located presynaptically that play a critical role in the release of NT from synaptic vesicles
drugs that use voltage gated ion channels
anesthetics, anticonvulsants
neurotransmitter regulated gated ion channles regulated by
neurotransmitter interactions with specific receptros
NT gated channle examples
directly coupled ion channles, g protein couple ion channles
directly couple ion channles (NT gated)
Cl channel regulated by Gaba A rec –> NT include gaba, glutamate, glycine, Ach
drugs that use NT gated directly coupled ion channes
anesthetics, anticonvulsants, cholinergic drugs, setative-hypnotics
Gprotein ion channels (NT gated) use
cAMP, IP3, DAG, Ca as second messengers –> can open channles after binding and protein phosphorylation producing long term effects
Gprotein NT gated channels seein in
Ach, most amines (dopamine, NE, 5HT) and peptides (endorphins)
drugs that use NT gated Gprotein channesl
analgesics, antidepressants, antipsychotis, anxiolytics
CNS neurotransmiters
Amino acids, biogenic amines, others
CNS NT - AA
glutamate, gaba, glycine
CNS NT - Biogenic amines
NT, Dopamine, Serotonin
CNS NT - others
Ach, substance P, Enkephalin
Glutamic acid is
excitatory via influx of cations using direct copuling and gproting linked
Glutamic acid recptor example
NMDA receptor
target of NMDA receptor
Ketamine, Phencyclidine
Gaba is
inhibitory via inc Cl in flux and K efflux
Gaba activities increase by
anticonvusants, sedatives, hypnotics, muscle relaxants
Gaba receptors
A and B
Gaba A receptor
coupled to Cl ion channle, activation leads to Cl running into cells (hyperpolarization)
Gaba B receptor
coupled to K ion channle, activation leacds to K efflux (hyperpolarization)
Ach on M1
excitatory - dec K+ efflux via DAG
Ach on M2
inhibitory - inc K efflux via cAMP
Ach on N
excitatory - na influx via direct coupling
baclofen binds
gaba B receptor
Muscuranic blockers are used in
parkinsons
AChE inhibitors are used in
Alzheimers
Dopamine is mainly
inhibitory, 5 subtypes
Dopamine activities increase by
CNS stimulants and anti-Parkinsons drugs
Dopamine activites decrease by
antipsychotics
NE is
excitatory or inhibitory, depending upon receptor subtypes (secon messenger coupling) - activities modifed by CNS stimulants, antidepressants, and some anxiolytics
Serotonin (5HT) is
excitatory or inhibitory, depending upon receptor subtype - activites modified by CNS stimulants, antidepressants, and some anxiolytics
Opioid peptides are
inhibitory - several subtypes, secon messenger coupling - activites modifed by opiod analgesics
glutamic acid on excitatory recpetors are antagonized by
ketamine, phencyclidine, and newer antiepileptics
gaba on ihibitory receptor GabaA drug agonsits
sedative -hypnotics and anti epileptic drugs
gaba on inhibitory receptot GabaB drug agonists
baclofen
Ach on M1 receptro(excitatory) antagonists
atropine (m blockers) block both M1 and M2
Ach on M2 receptor (inhibitory)
atropine
5HT3 causes vomiting so use
5HT3 blockers as antiemetics
Ach N receptor is
excitatory
Dopmapine receptor antagonis (mostly inhibitory receptors - some excitatory rec)
antipsychotics, antiparkonsonian drugs, amphetamines, cocain
NE is amplified by
MAO inhibitors, TCA, amphetamines, cocaine
Serotonin is amplified by
MAO inhibitors, SSRIs, TCA, some SNS stimulants and hallucinogens
Opiod peptides are amplified by
opiod analgesics
opiode peptieds are antagonized by
naloxone, naltrexone
Ach is involved in
arousal, short term memory, learning
NE is involved in
arousal, wakefulness, mood, cardiovascular regulation
Serotoning is involved in
feeding behavior, control of body temp, regulation of mood, emotion and sleep –wakefulness cycles
glycine is
an inhibitory NT that increases the entry of chlride into the post synaptic neurone, resulting in hperpolarization in the brain stem and spinal cord
Strychinine action
inhibits the glycine receptors resulting in muscular contractions and tetany
Substantce P mediates
the pain withing the spinal cord
Enkephalin mediates
the analgesia and other CNS effects