Neurotransmitters and Neuropeptides

Flashcards covering neurotransmitter synthesis, release mechanisms, receptor types (ionotropic vs. metabotropic), specific monoamine pathways (Dopamine, Serotonin, Norepinephrine), and neuropeptide characteristics.

Neurotransmitters are synthesized from __________ obtained from food.

amino acids

To reach the neurons, nutrients must cross the __________ after entering the bloodstream.

Blood Brain Barrier

The arrival of an action potential at the axon terminal triggers the opening of voltage-gated __________ channels.

$$Ca^{2+}$$

Neurotransmitter release into the synaptic cleft occurs when calcium binds __________ proteins, causing the vesicle to fuse with the presynaptic membrane.

docking

Storing neurotransmitters in vesicles protects them from __________ in the cytoplasm.

degrading enzymes

__________ receptors are ligand-gated ion channels that provide a fast response by directly opening ion channels.

Ionotropic

Metabotropic receptors are G-protein coupled receptors (GPCRs) that consist of three subunits: $\alpha$, $\beta$, and __________.

$$\gamma$$

Presynaptic __________ provide negative feedback by decreasing neurotransmitter synthesis and release.

autoreceptors

The three main monoamine neurotransmitters synthesized from tyrosine are Dopamine (DA), __________, and Epinephrine.

Norepinephrine (NE)

The enzyme __________ is responsible for converting Tyrosine into L-DOPA.

Tyrosine Hydroxylase (TH)

The dopamine circuit originating in the Substantia Nigra and projecting to the striatum is primarily associated with __________.

motor control

The dopamine circuit originating in the __________ and projecting to the limbic system is associated with reward and motivation.

Ventral Tegmental Area (VTA)

D1 receptors increase cAMP levels by activating the enzyme __________, making the neuron more excitable.

Adenylyl cyclase

The __________ dopamine receptor is inhibitory and works through the $G_i$ protein to decrease cAMP.

D2

Norepinephrine cell bodies are primarily located in the __________.

locus coeruleus

Serotonin ($5-HT$) is synthesized from the amino acid __________.

Tryptophan

While most serotonin is found in the gut, the serotonin neurons in the brain are located in the __________ of the brainstem.

Raphe Nuclei

Unlike small-molecule neurotransmitters, neuropeptides are made from __________ that are transcribed in the nucleus.

genes

__________ are neuropeptides released in response to exercise and stress, providing pain control and euphoria.

Endorphins

Oxytocin is produced by magnocellular neurons in the Paraventricular nucleus (PVN) and the __________.

Supra optic nucleus (SON)

The neuropeptide __________ promotes social behavior, mother-infant bonding, and reduces social anxiety.

Oxytocin

The enzyme responsible for converting L-DOPA into Dopamine (DA).

DOPA Decarboxylase (DDC)

The enzyme responsible for converting Dopamine (DA) into Norepinephrine (NE).

Dopamine β-hydroxylase (DBH)

The enzyme responsible for converting Norepinephrine (NE) into Epinephrine.

Phenylethanolamine N-methyltransferase (PNMT)

The amino acid from which Serotonin ($5-HT$) is synthesized.

Tryptophan

Neuropeptides released in response to exercise and stress, providing pain control and euphoria.

Endorphins

A type of neuropeptide that can modulate pain and stress responses.

Enkephalins

Neuropeptides that are involved in the regulation of mood and stress.

Dynorphins

The neuropeptide that serves several functions including pain modulation and emotional responses.

Endorphins