NEUROTRANSMITTERS, ENZYMES, CHEMICALS, HORMONES

Glutamate

Principal excitatory neurotransmitter in the brain

Glutamate

An excitatory neurotransmitter used by the cortex, thalamus, and STN

GABA

Major inhibitory neurotransmitter in the brainstem and spinal cord

GABA

Most important inhibitory neurotransmitter in the CNS

GABA

An inhibitory neurotransmitter used by the striatum, GPe, GPi, and SNr

Dopamine

A neurotransmitter produced in the SNc

Dopamine

A neurotransmitter produced in the Ventral Tegmental Area (VTA)

Dopamine

Has excitatory influence on the direct pathway (D1) in the Basal Ganglia

Dopamine

Has inhibitory effect on the indirect pathway (D2) in the Basal Ganglia

Dopamine

Plays a very important function in modulating motor movements

Dopamine

Its dysfunction in the mesolimbic pathway is linked to addiction and psychosis

Dopamine

Its dysfunction in the mesocortical pathway is linked to cognition and negative symptoms of schizophrenia

Dopamine

Its dysfunction in the tuberoinfundibular pathway inhibits prolactin secretion

Dopamine

Also known as a prolactin-inhibiting factor

Dopamine

Considered a signal for food, sex, and other needs

Dopamine

Attributed to the feeling of euphoria due to its relationship to the limbic system

Dopamine

Stimulates adenylyl cyclase activity via D1-like receptors

Dopamine

Inhibits adenylyl cyclase activity via D2-like receptors

Dopamine

Promotes wakefulness and modulates REM sleep

Dopamine

The amino acid tyrosine is its precursor

Acetylcholine (ACh)

An excitatory neurotransmitter

Acetylcholine (ACh)

Mediates synaptic transmission in the central, peripheral, and autonomic nervous systems

Acetylcholine (ACh)

Associated with learning and memory in the CNS

Acetylcholine (ACh)

Primary neurotransmitter of the preganglionic fibers of the ANS

Acetylcholine (ACh)

One of the REM sleep generators

Acetylcholine (ACh)

Involved in heterogeneous sleep-wake transition

Acetylcholine (ACh)

Neuronal firing is maximum during wakefulness and REM sleep

Acetylcholine (ACh)

Carries out Long-Term Potentiation related to memory

Acetylcholine (ACh)

Has two classes of receptors: Nicotinic and Muscarinic

Acetylcholine (ACh)

Degradation inhibitors are used for patients with dementia

Acetylcholine (ACh)

A minimal reduction in its transporter levels is associated with mild cognitive impairment

Acetylcholine (ACh)

Reduced levels in the synapse lead to less synaptic transmission

Serotonin

A monoaminergic neurotransmitter

Serotonin

Present in high concentrations in the brain stem

Serotonin

Located in the Raphe nuclei

Serotonin

Involved in regulation of mood and affect

Serotonin

Involved in REM sleep inhibition

Serotonin

Pathways involve mood, sleep, cognition, and memory processing

Serotonin

Formed from the amino acid tryptophan

Norepinephrine (NE)

A monoaminergic neurotransmitter

Norepinephrine (NE)

Located in the Locus Coeruleus (pons)

Norepinephrine (NE)

Its projections are widespread throughout the brain and spinal cord

Norepinephrine (NE)

Has a vital role in the modulation of cognition, arousal, attention, and stress responses

Norepinephrine (NE)

Considered the neurotransmitter for "Flight or fight" response

Norepinephrine (NE)

Promotes wakefulness and arousal

Norepinephrine (NE)

Facilitates sensory signal detection

Norepinephrine (NE)

Influences cognition and behavior, including working memory and attention

Norepinephrine (NE)

Involved in REM sleep inhibition

Norepinephrine (NE)

Stimulation or inhibition of memory retrieval is dependent on its receptor agonism or antagonism

Norepinephrine (NE)

The amino acid tyrosine is its precursor

Norepinephrine (NE)

Is converted to epinephrine in the CNS and adrenal medulla via the enzyme phenylethanolamine N-methyltransferase (PNMT)

Histamine

A monoaminergic neurotransmitter

Histamine

Produced in the Tuberomammillary nucleus (TMN) of the hypothalamus

Histamine

Involved in arousal and wakefulness

Histamine

Involved in learning, homeostasis, sleep-wake cycle, and synaptic plasticity

Orexin (Hypocretin)

A neurotransmitter produced in the Tuberomammillary nucleus of the hypothalamus

Orexin (Hypocretin)

Adds up to the wakefulness circuitry

Orexin (Hypocretin)

Its receptor antagonists are used in the treatment of narcolepsy

Glycine

Major inhibitory neurotransmitter in the brainstem and spinal cord

Glycine

Acts as a coagonist at the NMDA glutamate receptors

Glycine

Binding to its receptor results in hyperpolarization via influx of chloride ions

Melatonin

A sleep promoter neurotransmitter/hormone

Melatonin

A monoaminergic hormone synthesized in the Pineal Gland

Melatonin

Its secretion is stimulated by darkness and inhibited by light

Melatonin

Metabolized in the liver (hepatic)

Melatonin

Regulates the sleep-wake cycle

Synaptotagmin

A v-SNARE protein that detects the entry of Ca2+ and triggers fusion by binding with Ca2+

Synaptobrevin

A v-SNARE protein that attaches with t-SNAREs like syntaxin and SNAP-25

Syntaxin

A t-SNARE protein found in the terminal membrane

SNAP-25

A t-SNARE protein found in the terminal membrane

Nicotinic receptors

Acetylcholine receptors that are Ion channels for sodium and calcium

Nicotinic receptors

Located in the plasma membranes of dendrites and cell bodies of postganglionic neurons

Nicotinic NN receptors

Located in autonomic ganglia, adrenal medulla, and CNS

Nicotinic NM receptors

Located at the motor end plate at the neuromuscular junction

Muscarinic receptors

Acetylcholine receptors that are G-protein coupled

Muscarinic receptors

Located in the plasma membranes of all effectors innervated by parasympathetic postganglionic axons

Alpha-adrenergic receptors (α1, α2)

Norepinephrine receptors involved in attention and memory

Beta-adrenergic receptors (β1, β2, β3)

Norepinephrine receptors

Beta-adrenergic receptors (β1, β2)

Norepinephrine receptors involved in memory retrieval and spatial reference

D1-like receptors (D1, D5)

Dopamine receptors that are excitatory

D2-like receptors (D2, D3, D4)

Dopamine receptors that are inhibitory

NMDA receptors

An ionotropic glutamate receptor that is a cation channel

AMPA receptors

An ionotropic glutamate receptor that is a cation channel

Kainate receptors

An ionotropic glutamate receptor that is a cation channel

mGluRs (Metabotropic glutamate receptors)

Glutamate receptors that are G-protein coupled and have slow effects

Histamine receptors (H1, H2, H3, H4)

Receptors that histamine acts upon

Acetylcholinesterase (AChE)

The enzyme that degrades ACh to acetyl CoA and choline

Monoamine oxidase (MAO)

An enzyme that degrades norepinephrine intracellularly or in the synaptic cleft

Catechol-O-methyltransferase (COMT)

An enzyme that degrades norepinephrine intracellularly or in the synaptic cleft

Glutamate Acid Decarboxylase (GAD)

The enzyme that converts glutamate to GABA

Phenylethanolamine N-methyltransferase (PNMT)

The enzyme that converts norepinephrine to epinephrine

Tryptophan-5-hydroxylase

The enzyme involved in the rate-limiting step of serotonin synthesis, converting tryptophan to 5-HTP

Ca2+

Ion whose influx into the presynaptic terminal causes release of neurotransmitters

Ca2+

Its entry is detected by synaptotagmin to trigger synaptic vesicle fusion

Ca2+

Approximate equilibrium potential in nerve and muscle is +120 mV

Ca2+

Inward movement depolarizes the cell membrane

Na+

Approximate equilibrium potential in nerve and muscle is +65 mV

Na+

Inward movement depolarizes the cell membrane

K+

Approximate equilibrium potential in nerve and muscle is -85 mV

K+

Outward movement hyperpolarizes the cell membrane