NTs 2 b

Question 1

neuropeptides: 5 categories

Answer 1

hypothalamic releasing hormones, neurohypophyseal hormones, pituitary peptides, gastrointestinal peptides, and other

Question 2

neuropeptides act through what receptors?

Answer 2

heptahelical G protein and 2nd messengers. NOT ionotropic receptors. can also change ion fluxes.

Question 3

neuropeptides: synthesis? rate, transport, abundance?

Answer 3

synthesized on ribosomes in cell bodies; rate controlled at cell body then peptide slowly transported to terminals via axonal transport and releasable peptide soon runs out

Question 4

neuropeptides released by? characteristics of transmission

Answer 4

intense nerve activity: expensive but very effective and act over a wide area. volume transmission/slow synpatic potentials

Question 5

peptides typically cleaved from? ex?

Answer 5

large precursor molecules by specific proteases. ex POMC into ACTH, b-LPH, a-MSH, edorphins and enkephalins, etc.

Question 6

veiscles for neuropeptides vs. NTs

Answer 6

synaptic vesicle built around peptide as it is processed vs. conventional NTs are transported into vesicles

Question 7

NTs into vesicles how?

Answer 7

proton pump (using ATP) makes inside very acidic. transmitter transporter: H+ leaves via concentration gradient, transmitter goes in

Question 8

substance P: size? family?

Answer 8

11 amino acids. tackykinins: also includes neurokinin A and B

Question 9

substance P involved in what 4 things

Answer 9

peristaltic reflex in enteric neurons. reflex pathways in prevertebral sympathetic ganglia. neurogenic inflammation (axon reflex) neuro-immune interactions

Question 10

substance P in CNS: 2 roles

Answer 10

transfer of painful ino. anxiety, depression, emesis control (vomiting)

Question 11

substance P actions outside NS (3)

Answer 11

arteriole vasodilator but constricts veins. constricts bronchioles and intestinal smooth muscle. salivary secretion.

Question 12

substance P: therapeutic interventions?

Answer 12

non peptide antagonists developed as potential analgesics but work better as antidepressants

Question 13

NPY: size? why called Y?

Answer 13

36 amino acids. rich in tyrosine = Y

Question 14

NPY: main role for transmission

Answer 14

co-transmitter for NA in sympathetic nerves that control blood vessels (vasoconstriction)

Question 15

NPY: in CNS?

Answer 15

involved in control of feeding and BP: intraventricular injection of NPY = feeding. maybe use antagonists for obesity treatment

Question 16

2 NPY receptors and their transduction cascade and effect

Answer 16

Y1 receptors (like a1) G1 coupled, PLC, IP3, Ca for smooth muscle contraction. Y2 (like a2) Gi/o coupled, inhibit presynpatic Ca channel currents = decreased transmitter release (presynpatic)

Question 17

3 opioid peptides

Answer 17

enkephalins. dynorphins. endorphins.

Question 18

enkephalins: two examples and sizes? made from? distribution?

Answer 18

leucine and methionine enkephalins both chains of 5 aas. cleaved from larger 267 aa proenkephalin. in neurons widely distributed in the brain

Question 19

dynorphins: size, made from

Answer 19

30 aa long. four smaller peptides derived from prodynorphin which is 257 aa long

Question 20

endorphins: mainly found where?

Answer 20

imunoreactive cell bodies are mainly found in arcuate nucleus and periarcuate regions of hypothalamus. also found in brainstem + pit gland

Question 21

opoid receptors: 3 types? category? also bind what drugs?

Answer 21

mu, delta, kappa. G protein coupled. morphine and heroin

Question 22

mu-receptors (opioid) for?

Answer 22

important role in regulation of pain transmission in SC and CNS

Question 23

opoid receptor stimulation causes what 6 things

Answer 23

analgesia. constipation. respiratory depression. euphoria. sedation. meiosis (pinpoint pupils, parasymp)