3.2 Chemical Events at the Synapse Flashcards
Amino acids
Acids containing an amine group (NH2)
Monoamines
Chemicals formed by a change in certain amino acids
Acetylcholine
(A one-member “family”)
A chemical similar to an amino acid, except that it includes an N(CH3)3 group instead of an NH2
Neuropeptides
Chains of amino acids
Purines
A category of chemicals including adenosine and several of its derivatives
Gases
Nitric oxide and possibly others
Nitric oxide
Chemical formula NO, a gas released by many small local neurons.
NB! Do not confuse nitric oxide, NO, with nitrous oxide, N2O, aka “laughing gas”
MAO (monoamine oxidase)
Enzyme that converts catecholamines and serotonin into synaptically inactive forms
Eg. Several antidepressant drugs inhibit MAO
Exocytosis
A release of neurotransmitter from the presynaptic neuron into the synaptic cleft that seperates one neuron from another
Ionotropic effects
Synaptic effects that depend on the rapid opening of some kind of gate in the membrane
Transmitter-gated or ligand-gated channels
Ion channel that opens temporarily when a neurotransmitter binds to it
Metabotropic effect
A sequence of metabolic reactions that produce slow and long-lasting effects at a synapse
G-protein
A protein coupled to guanosine triphosphate (GTP), an energy-storing molecule
Second messenger
A chemical that, when activated by a neurotransmitter, initates communication to many areas within the neuron
Neuropeptide Y (NPY)
Peptide that blocks the satiety actions of the paraventricular nucleus
Neuromodulators
Researchers often refer to neuropeptides as neuromodulators, because they can influence the function of neurons but do not act as neurotransmitters
Neurogliaform cell
A kind of neuron that releases huge amounts of GABA all at once, producing widespread inhibition
Hormone
Chemical that is secreted by cells in one part of the body and conveyed by the blood to influence other cells
Neurotransmitters
Chemicals released by neurons that affect other neurons
Endocrine glands
Hormone-producing glands
Protein hormones
Hormones composed of long chains of amino acids
Peptide hormones
Hormones composed of short chains of amino acids
Pituitary gland
An endocrine gland attached to the base of the hypothslamus
Anterior pituitary
Portion of the pituitary gland, composed of glandular tissue
Posterior pituitary
Portion of the pituitary gland, which releases hormones synthesized by the hypothalamus
Oxytocin
Hormone released by posterior pituitary; important for sexual and parental behaviours
Vasopressin
Antidiuretic hormone. Hormone released by posterior pituitary; raises blood pressure and enables kidneys to conserve water
Releasing hormone
Hormone released by the hypothalamus that flows through the blood to the anterior pituitary
Acetylcholinesterase (a-SEE-til-ko-lih-NES-teh-raze)
An enzyme that breaks down the neurotransmitter acetylcholine into two fragments: acetate and choline
Reuptake
Reabsorption of a neurotransmitter by the presynaptic terminal
Transporters
Special membrane protein where reuptake occurs in the neurotransmitter
COMT (catechol-o-methyltransferase)
Enzyme that breaks down exess dopamine into inactive chemicals that cannot stimulate the dopamine receptores
Autoreseptors
Receptors that respond to the released transmitter by inhibiting futher synthesis and relase. That is, they provide negative feedback
Gap junction
A direct contact of one neuron with another, enabling electrical transmission
