-
Most drugs work at the?
synapses
*except anesthetics that block Na+ channels, that stop action potentials to propegate- =membrane stabilizers
-
most abused drugs come from? and either inhibit or____ transmission of NT
a: plants b: facilitate
-
Drugs can stimulate or block ____ receptors?
- a: post-synaptic
- *can block or breakdown NT at the synapse
- *can increase or decrease synthesis of NT
- *can cause vesicles to leak
- *can block reuptake of NT back into the presynaptic cell
-
Nucleus accumbens- important for ?
Many axons that input into this area release what?
- a: receiving pleasure
- b: dopamine or NE
-
Nucleus accumbens is activated when?
-sexual excitement, gambling, habitual video player, other drugs
-
Wanting=
motivation, may want a pHd but don't enjoy getting it
-
liking =
enjoying the experience, but don't always want it
-
The bigger parts of the nucleus accumbens responds more to the?
wanting/motivation
-
addictive drugs activate nucleus accumbens by releasing what?
DA or Ne on to it
-
Stimulant drugs increase concentration of DA in the synapses in the NA
Amphetamine & cocaine block protein therefore increasing the DA concentration
-
Amphetatime has some similar effects on 5-HT and NE transport proteins and Methamphetamines have a ____ effect than Amphetamine
stronger
-
Stimulants make you feel depressed after use because?
The DA is washed away and the brain can't make Dopamine fast enough so you end up with a deficit of DA in the Synaptic cleft
-
What is the synaptic cleft?
- This is the junction between two neurons. At the one end you have the
- pre-synaptic membrane - the terminal end of the previous neuron, the
- pre-synaptic neuron - and on the other side you have the post-synaptic
- membrane, part of the post-synaptic neuron. Action potentials typically
- cross the cleft by the use of neurotransmitters.
-
Stimulants: high doses impair attention, learning, depression
low doses = good for
Rx of ADHD- enhances attention
-
Methylphenidate(Ritalin) blocks what?
reuptake of DA and NE
-*injecting ritalin = same effect as cocaine
-
Methamphetamine: Increases DA in Syn-cleft
-medically approved low dosage for ADHD & obesity(desoxyn)
- *high doses = mania, grandiosity, increased libido
- *increases Parkinsons Dz, cognitive deficits, impairs attention/memory. 20% experience psychosis like schizophrenia -difficult to treat
- -*LONT-TERM = depression, suicide, heart, "meth mouth"
-
Nicotin-
- stimulates Ach receptors = Ach receptor agonist
- *releases DA and NE in nucleus accumbens
- *used as an insectiside
-
OPIATES =
morphine, heroin, methadone
-
OPIATES - brain produces its own version called__?
Effects are?
a: endorphins
B: relaxation, pain relief, decreased anxiety
-
Opiates ___ activate DA release. Endorphins ____ neurons that release ___?
a: inderectly b: inhibit c: GABA
*GABA- inhibits firing neurons that release DA, so by inhbiting the inhibitor GABA the effect increases DA release
-
Marijuana contains? and affects are?
Cannabinoids/THC
- *good for appetite, pain, & nausea
- -But impairs memory & cognition- betters with 4 weeks after stopping use
-
Marijuana- has very few Cannabinoid receptors in the Medula so it doesn't have much of an effect on____?
heart rate, or breathing like opiate receptors
-
Marijuana receptors are located in the ___ neuron?
Presynaptic
-
Marijuana: When the post-synaptic neuron is stimulated it releases the cannabinoid ---
- The cannabinoid travels back to the presynaptic neuron & inhibits further release of eitehr glutamate or GABA
- * so the chemicals in Marijuana decrease both Inhibit & excite transmissions in the synapse.
-
Marijuana- decrease inhibition due to ___?
decreased GABA release of neurons that release DA on Nucl-accumbens
-
Hallucinogenic Drugs =
LSD, - Extasy(MDMA) at low doses release DA similar to Amphetamine.
- -Higher doses- affects 5-HT receptors. destroys neurons, increases body temp., life threatening
- *long-term = loss of serotonin receptors, depression, anxiety, impaired learning/memory
-
What drugs block re-uptake of dopamine and other transmitters and also excite, elevate, & enhance alertness?
Amphetamines, Cocaine,
-Methylphendine(ritalin)- mainly just alerts
-
MDMDA (exctasy) - Low dose =
and High dose =?
a: stimulator = releases Dopamine
B: distorts senses = releases serotonin *damages axons containing serotonin
-
Nicotine = mostly stimulant effects... stimulates Nicotinic receptors that __?
increase DA in N-accumbens
-
Opiates; heroin, morphine- relax, withdrawl, decreased pain and stimulates _____?
endorphin receptors
-
Marijuana- alters senses, decrease pain/nausea, increased appetite and excites ____?
negative-feeback receptors in presynaptic cells: those receptors ordinarily respond to anandamide cells and 2AG
-
Hallacinagens - distorted sensations-- *stimulates ___?
serotonin type 2A receptors
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