Biopsychology: Neurotransmitters

Agonistic Drug Effects

-Interferes with enzymes -Binds to the autoreceptors and blocks them -Binds to postsynaptic receptors and activate them -Interferes with cleanup mechanisms -Interferes with reputake mechanisms

Antagonistic Drug Effects

-Interferes with synthesis process/breaks down precursors -Interferes with releasing mechanism -Binds to autoreceptors and activates them -Binds to postsynaptic receptors and blocks them

Synaptic Events (mechanisms)

-Synthesis of neurotransmitter -Storage in vesicles -Breakdown in cytoplasm of any neurotransmitter that leaks from the vesicles -Exocytosis -Inhibitory feedback via auto receptors -Activation of post synaptic receptors -Deactivation

Dopamine

A catecholamine neurotransmitter that comes from the synthesis of L-dopa and is associated with movement, attention and learning and the brain's pleasure and reward system.

Norepinephrine

A catecholamine neurotransmitter that comes rom the synthesis of Dopamine and is mostly an excitatory neurotransmitter found in the autonomic nervous system. It stimulates activity in the sympathetic nervous system, regulates the fight v. flight response, and is involved in alertness and wakefulness.

Epinephrine

A catecholamine neurotransmitter that comes rom the synthesis of Norepinephrine. It's an excitatory neurotransmitter involved in regulating the fight v. flight response, increasing activity in the sympathetic nervous system, regulating cardiovascular functions and blood pressure, and adrenaline if coming from adrenal glands.

Indolamines

A family of neurotransmitters that share a common molecular structure. Common examples are serotonin and melatonin.

Acetylcholine

A neurotransmitter found in both central and peripheral nervous systems. CNS- regulates sleep and arousal, related to Alzheimer's disease PNS- Excitatory, responsible for muscle contractions ANS- Inhibitory on smooth muscles (heart, intestines, organs)

Acetylcholine Synthesis

Acetyl Coenzyme A and Choline--->Choline Acetyltransferase--->Acetylcholine --->Acetylcholinesterase--->Acetyl Coenzyme A and Choline

Monoamine Oxidase (MAO)

An enzyme that breaks down catecholamines and indolamines into its precursors so they can be reused and recycled; Two forms A and B. -Norepinephrine and Epinephrine are mainly broken down by A -Serotonin is mainly broken down by A, but also by B in various parts of the NS -Dopamine is broken down by both A and B

Acetylcholinesterase

An enzyme that breaks down the neurotransmitter acetylcholine by removing the Choline from the acetate ion to make them no longer active.

Serotonin (5-hydroxytryptamine)

An inhibitory neurotransmitter that comes from the synthesis of Tryptophan and 5-HTP. It stabilizes and relaxes your mood, regulates hunger, eating, appetite, and learning/memory.

Adrenergic

Communication between the nerves and muscles that uses epinephrine as the 'messenger.' _______ stimulation is what is involved in the 'flight or fight' response, results in an increased heart rate, sweating, and increased blood pressure.

Antagonistic Mechanisms

Drug that decreases the function of a neurotransmitter by working in the opposite directions of its typical effect. If a neurotransmitter is excitatory it will decrease the possibility of an action potential; If a neurotransmitter is inhibitory it will make it more likely to create an action potential by doing the opposite of what normally happens.

Agonistic Mechanisms

Drug that facilitates the function of a neurotransmitter by enhancing its typical effect. If a neurotransmitter is excitatory it will open sodium channels and increase the chance of an action potential; If a neurotransmitter is inhibitory it will open potassium channels and hyperpolarize the neuron to make it less likely for an action potential to occur.

Monoamines

General term for neurotransmitters that derive from one amino acid.

Precursor

Molecules that are necessary for synthesis for a particular neurotransmitter.

Amino Acid Neurotransmitters

Most common neurotransmitter in fast-acting, directed synapses in CNS; Molecular building blocks of proteins.

5-HTP (5-hydroxytryptophan)

Product of Tryptophan synthesis and precursor to Serotonin.

Noradrenergic

Referring to systems using norepinephrine as a transmitter; believed to modulate many behavioral and physiological processes, including mood, overall arousal, and sexual behavior.

Neuromodulator (Neuropeptide)

Short amino acid chains released in the nervous system that influence the sensitivity of the receiving neuron to neurotransmitters.

Choline Acetyltransferase

The enzyme that enables the transfer of the acetate ion from acetyl Coenzyme A to Choline to create Acetylcholine (ACh)

Antagonist

The following are all examples of an ______: Botulinum toxin- inhibits release of ACh Curare- blocks postsynaptic receptors of ACh Atropine- blocks postsynaptic receptors of ACh

Agonist

The following are all examples of an ______: Cocaine- blocks reuptake of dopamine; triggers increase of dopamine Nicotine- binds to the same postsynaptic receptors as acetylcholine and stimulates them to increase the functioning of ACh L-Dopa- precursor molecule for dopamine; increases synthesis of dopamine

Glutamate

The most prevalent excitatory neurotransmitter in the nervous system; involved in memory and learning. It depolarizes neurons and facilitates action potentials; Very common in proteins that we eat.

GABA

The most prevalent inhibitory neurotransmitter in the nervous system. Synthesized by a simple change to Glutamate; Reduces the risk of firing in the neuron, hyperpolarizes neurons.

Catecholamines

The neurotransmitters dopamine, epinephrine, and norepinephrine, which are active in both the brain and the peripheral sympathetic nervous system. These three molecules have certain structural similarities and are part of a larger class of neurotransmitters known as monoamines.

Tryptophan

The precursor amino acid that Serotonin is synthesized from.

Tyrosine

This amino acid is the first precursor for all catecholamines

Monoamine Synthesis

Tryosine--->L-dopa--->Dopamine --->Norepinephrine--->Epinephrine

Serotonin Synthesis

Tryptophan--->5-HTP--->Serotonin

Acetyl Coenzyme A and Choline

Two precursors that are combined to form ACh in the axon terminal

L-dopa

Tyrosine is acted upon by an enzyme and creates ______, a small molecule that can cross over the BBB into the CNS and is a precursor for Dopamine/Catecholamines. Used in Parkinson's treatment.

Directed Synapse

When the site of neurotransmitter release and the site of receptor is close. This is the most typical synapse.

Indirected Synapse

When the site of the neurotransmitter release is further up the terminal in small bulges that line up next to each other and when they are released the diffuse further and contact other neurotransmitters in the vicinity.