EXAM I Intro to the Nervous System Flashcards Preview

Human Disease and Therapeutics > EXAM I Intro to the Nervous System > Flashcards

Flashcards in EXAM I Intro to the Nervous System Deck (29)
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1
Q

describe the general principles of direct actions of neurotransmitters

A
  • NT binds to and opens ion channels
  • promotes rapid responses by altering membrane potential
2
Q

describe the general principles of indirect actions of neurotransmitters

A
  • NT acts through intracellular second messengers, usually G protein pathways
  • broader, longer-lasting effects
3
Q

___ is an excitatory neurotransmitter

A

glutamate

4
Q

___ and ___ are inhibitory neurotransmitters

A

dopamine and GABA

5
Q

___, ___, and ___ are both excitatory and inhibitory neurotransmitters

A

acetylcholine, norepinephrine, and serotonin

6
Q

is GABA a direct or indirect acting neurotransmitter?

A

direct

7
Q

___ membrane channels open and close in response to voltage changes across the membrane; what are some examples?

A
  • voltage-gated
  • examples: voltage-gated Na+ channels and lidocaine
8
Q

___ membrane channels involve a hormone, drug, or transmitter than bind to the protein and the channel opens up; what are some examples?

A
  • ligand-gated (ionotropic)
  • examples: glutamate (AMPA), nicotine ACh receptors, and GABA
9
Q

what is the action length of ligand-gated (ionotropic) receptors?

A

action is immediate and brief

10
Q

are ligand-gated (ionotropic) receptors excitatory or inhibitory?

A
  • some are excitatory and open channels for small cations
  • some are inhibitory and allow Cl- influx or K+ efflux to cause hyperpolarization
11
Q

T or F:

metabotropic receptors are not directly linked to ion channels

A

true

12
Q

how do metabotropic receptors work?

A
  • initiates a biochemical process that mediates more long-term effects and modifies the responsiveness of the neuron
  • NT acts as the first messenger which activates a second messenger that in turn changes the excitability of a neuron
13
Q

what are the two types of metabotropic receptors?

A
  • membrane-delimited - occur entirely in plane of membrane
    • when G-proteins interact with calcium channels, they inhibit channel function (presynaptic inhibition)
    • when G-proteins interact with K+ channels, they open (activate) channels causing postsynaptic inhibition
  • diffusible second messengers
14
Q

what are examples of diffusible second messengers (metabotropic)?

A

beta-adrenergic receptors and cAMP

15
Q

___ are receptors on an axon terminal through which the neuron’s own NT can influence the function of the terminal (usually inhibitory) - for example, D2 receptors

A

autoreceptors

16
Q

___ are receptors on an axon terminal through which NTs from other neuronal types can influence the function of the terminal

A

heteroreceptor

17
Q

what are the 3 catecholamines?

A

dopamine, norepinephrine, and epinephrine

18
Q

___ can act like dopamine due to its similar structure

A

amphetamine

19
Q

which enzyme catalyzes the conversion of NE to epi?

A

phenylethanolamine-N-methyltransferase (PNMT)

20
Q

epinephrine is typically made by ___, but can also be made by some ___

A
  • adrenal medullary cells
  • CNS neurons
21
Q

what is a monoamine?

A

one amino group connected to an aromatic group by a 2-carbon chain

22
Q

what are 3 exmamples of monoamines?

A

catecholamines, serotonin, histamine

23
Q

is serotonin a catecholamine?

A

no, it is an indoleamine

24
Q

which amino acid is inhibitory?

A

GABA

25
Q

which amino acid is excitatory?

A

glutamate

26
Q

H3 (histamine) receptor is thought to function as an ___

A

inhibitory heteroreceptor

thus, activtaion of brain H3 receptors decreases the release of acetylcholine, dopamine, norepinephrine, serotonin, and certain peptides

27
Q

what is neurotensin? where is it found?

A
  • a neuropeptide that acts as an endogenous neuroleptic and regulates dopamine systems (inhibitory feedback)
  • it is found in the GI tract (inhibits GI motility) and circulation (causes vasodilation)
28
Q

describe nitric oxide

A
  • gaseous signaling molecule
  • CNS role is controversial
  • relaxes vascular smooth muscle
29
Q

how do endorphins make you happy?

A

endorphins bind to µ receptors, causing a decrease in GABA release, which causes an increase in dopamine release (= happy feeling)