Neurotransmitters & Receptors Flashcards

Acetylcholine

• Functions within cholinergic systems through nicotinic and muscarinic receptors.
• Biochemical synthesis involves acetyl-coenzyme A and choline, catalyzed by choline acetyltransferase; broken down by acetylcholinesterase into acetate and choline.
• Peripheral roles include muscle contraction at the neuromuscular junction and regulation of visceral functions in the autonomic nervous system.
• Central roles encompass autonomic regulation and selection of attention focus.

Amino Acids as Neurotransmitters

• Amino acids serve as primary neurotransmitters in the CNS, with two classifications:
  • Excitatory: aspartate and glutamate
  • Inhibitory: glycine and GABA

Glutamate

• Principal fast neurotransmitter involved in learning, development, and neuronal death following CNS injuries.

Glycine

• Functions as an inhibitory neurotransmitter, particularly affecting postsynaptic membranes in the brainstem and spinal cord.

GABA (Gamma-Aminobutyric Acid)

• Major inhibitory neurotransmitter in the CNS, particularly associated with interneurons in the spinal cord.

Monoamines

• Key neurotransmitters include dopamine, norepinephrine, serotonin, and histamine.
• Dopamine and norepinephrine are classified as catecholamines, derived from phenylalanine and tyrosine.

Catecholamine Synthesis

• Synthesized from phenylalanine through tyrosine to L-DOPA, then converted into dopamine, norepinephrine, and epinephrine.

Dopamine

• Influences motor activity, cognition, and motivation; critical in conditions such as Parkinson's Disease (low) and schizophrenia (high).

Norepinephrine

• Integral to the autonomic nervous system, facilitating fight-or-flight responses, as well as attention and vigilance.

Serotonin

• Regulates blood vessels, mood (low levels linked to depression), and sleep, affected by dietary tryptophan.

Histamine

• Concentrated in the hypothalamus, regulates hormonal functions, and plays a role in inflammatory responses.

Peptides as Neurotransmitters

• A broad category with diverse functions, primarily acting as neuromodulators rather than classical neurotransmitters.

Endogenous Opioid Peptides

• Includes endorphins, enkephalins, and dynorphins, involved in pain inhibition and hormonal regulation, binding to opiate drug receptors.

Substance P

• A neurotransmitter involved in pain perception, reflecting the importance of signaling in sensory pathways.

Other Peptides

• Significantly involved include ACTH, vasopressin, neurotensin, cholecystokinin, and somatostatin.

Nitric Oxide (NO)

• Functions as a neuromodulator affecting vascular regulation, neuronal cell death, and altering postsynaptic response to stimuli.

Carbon Monoxide (CO)

• Exhibits rapid, short-lasting effects that influence neurotransmitter release.

Types of Receptors

• Categories encompass acetylcholine, amino acids (glutamate, GABA), norepinephrine, dopamine, serotonin, and opioid peptides.

Nicotinic Acetylcholine Receptors

• Ligand-gated ion channels located at the neuromuscular junction and autonomic ganglia; play roles in memory and learning, with implications in Alzheimer's and neuronal development.

Muscarinic Acetylcholine Receptors

• Further elaboration needed for a complete overview.

Explore the intricate world of neurotransmitters with these flashcards focused on acetylcholine and its receptors. Learn about cholinergic systems, the biochemical pathways involved, and the peripheral role of acetylcholine. Perfect for students and enthusiasts alike.