chapter 4 pt. 2: Neurotransmitters (NTs)

Excitatory post-synaptic potential (EPSP)

 an excitatory depolarization of the PS membrane of a synapse caused by the activation of a NT by the terminal button

Inhibitory postsynaptic potential (IPSP)

an inhibitory hyperpolarization of the PS membrane of a synapse caused by activation of a NT by the terminal button

Neuromodulator

naturally secreted substance that acts as a NT except its not restricted to the synaptic cleft but diffuses through ECF; helps enhance/inhibit NTs

what are some NTs we’ll be tested on

amino acids, acetylcholine, monoamines, peptides, lipids (will be tested on)

3 important and most common amino acids are?

glutamate, gamma-aminobutyric acid (GABA), and glycine

Glutamate

principle excitatory NT in the brain and spinal cord (NMDA receptors, AMPA receptors, Kainate receptors, Metabotropic glutamate receptors)

GABA

primary inhibitory NT; widely distributed throughout the brain and spinal cord; produced from glutamic acid

GABA receptors

GABA(A) and GABA(B)

Glycine

Inhibitory NTs, mainly found within the spinal cord and brainstem; helps with processing of motor and sensory info, also involved in lockjaw

dorsolateral pons

ACh released; helps with REM sleep

basal forebrain

ACh released; facilitates learning

medial septum

ACh released; modulates formation of some memories

Acetylcholine

primary NT secreted by efferent axons of the peripheral NS

Functions of acetylcholine

• All muscular movement is due to release of ACh

• Also found in the ganglia of the ANS 

• Is secreted at target organs by the vagus nerve

what are the 2 main classes of ACh receptors?

nicotinic and muscarinic

nicotinic

 stimulated by nicotine blocked by curare; activation of these responsible for the addictive effect of nicotine; present in CNS and PNS

muscarinic

stimulated by muscarine blocked by atropine; actions are slower and more prolonged than nicotinic receptors; present in CNS and PNS

Monoamines

produced by several systems of neurons in the brain increases/decreases the activities of particular brain functions

categories of monoamines?

Catecholamines, Indolamine, Ethylamine

dopamine

involved in movement, attention, learning, reinforcing effects of drugs; Precursor: L-DOPA

chlorpromazine

used to block one type of dopamine receptor, alleviates hallucinations; used for schizophrenia

how is parkinson’s disease treated?

treated with L-DOPA

norepinephrine (NE)

 found in brain and sympathetic division of the autonomic nervous system

Epinephrine (aka adrenaline)

secreted just above the kidneys (adrenal medulla); part of fight or flight response, increases and maintains blood pressure, and increases energy use by body (breakdown stored fat and release sugars)

Serotonin (aka 5-HT)

helps with mood regulation, eating, sleep, arousal, pain regulation, dreaming; has at least 9 different types of receptors

PCPA

blocks activity of tryptophan hydroxylase (enzyme used in serotonin synthesis)..serotonergic antagonist

BuSpar

treat anxiety and depression, agnostic effect (binds to 5-HT receptor)

LSD

visual distortions had agonistic effect on receptors in forebrain

Prozac

used to treat depression, anxiety disorders, OCD, has agonistoc effect (reuptake inhibitor)

ecstasy/MDMA

excitatory and hallucinogenic effects, agonistic effect (reuptake inhibitor)

Histamine

produced from amino acids; functions with digestive system, wakefulness, and immune system

Peptides

two or more amino acids linked together created in the soma of the neuron and transported down the axon; main family is endogenous opioids; no mechanism for reuptake

opioid receptors

activated by endogenous peptides and exogenous drugs; when stimulated, causes analgesia is produced (pain reduction), inhibits defensive responses from the fight or flight response, reinforcement/rewards systems (where addiction stems from)

Opiates

derived from opium, common names: morphine, heroin, and oxycodone

Naloxone

aka narcan; reverse opiate intoxication or overdose

Lipids

 various substances are derived from lipids that can communicate withing and between cells

Endocannabinoids

natural ligands for the receptors responsible for the physio effects of marijuana

what are the cannabinoid receptors?

CB1 (found within the brain) and CB2 (found outside of the brain)

THC

aka tetrahydrocannabinol, stimulates cannabinoid receptors