Neurotransmitter Flashcards
NT at the skeletal NMJ
Ach
Biogenic amines
catecholamines (NE, E, Dopamine)
indolamines
Histamines
Dopamine
basal nuclei, limbic system, involved in motivation, drive reward, cocaine enhances the action of dopamine receptors
What is most important in determining if a NT is excitatory or inhibitory?
receptor type
Indolamines
most prevalent is serotonin, 5-HT, excitatory and inhibitory functions depending on the action of it’s 16 subtypes of receptors, holy grail of pharmacology
Histamines
inflammatory role in immune response, NT in posterior hypothalamus, modulate sleep/wakefulness
Destruction of HIstamine releasing neurons leads to an inability to stay awake. Anti-histamines can have this same effect.
control mechanisms by which memories and learning are forgotten
CNS NT
amino acid derivatives
excitatory AA derivatives
Glu, Asp, bind to excitatory receptor subtypes
PCP
binds to Glu receptors
inhibitory AA derivatives
GABA, receptor for GABA is a target of anti-anxiety drugs - benzodiazepines, enhances GABA secretion and production
Glycine - primarily at spinal cord (still CNS), binds to receptros associated with Cl- channels
tetanus toxin
inhibits the release of GABA
Which NT binds Cl- associated channels?
Gly, increase Cl- permeability in the post-synaptic neuron. cuases hyper polarization
Where does Gly play a big role?
at thalamus, filters info coming in
strychnine
competes for and blocks Gly receptors, no inhibition, too much excitement, hyerstimulation can lead to convulsions, hallucinations
Neuropeptides
2 or more AA strung together
substance P, high levels in SC and hypothalamus, found in neurons that transmit PAIN, think nociceptors, these detect damage to tissue and reflected as PAIN, burning sensation
also OPIOIDS - endorphins, enkephalins, and dynorphins
Capsaicin
there is a heat-activated Calcium channel which usually opens between 37-45 degrees C. CAPSAICIN lowers this temperature so neurons release substance P at a lower temperature.
Capsaicin patches depleted substance P. Sensation of “Heat” is really substance P being released. Pain “leaves” bc substance P runs out.
Opioids
endorphins, enkephalins, dynorphins, bind to same receptors as opium and morphine
sense of well-being, euphoria, runner’s high
Nitric oxide
mostly excitatory effects at CNS, peripheral effect, relaxes endothelial walls (inner portion of blood vessels capillary wall dynamics) cardiovascular disease, erectile tissue, Viagra increases NO levels
