36-CircadionRhythms

Question 1

circadian rhythm

Answer 1

cycle with period of approx. 24 hours

Question 2

zeitgeber

Answer 2

“time giver” (e.g. light/dark)

Question 3

FRP

Answer 3

free running period (i.e. no entrainment of circadian rhythm)

Question 4

SCN

Answer 4

suprachiasmatic nucleus

Question 5

SCN located at base of ___ overlying ___

Answer 5

hypothalamus, optic chiasm

Question 6

PER2

Answer 6

clock gene

Question 7

SCN receives direct input from ___

Answer 7

retina

Question 8

RHT

Answer 8

retino-hypothalamic tract

Question 9

IPRGCs

Answer 9

intrinsically photosensitive retinal ganglion cells

Question 10

SCN receives photic input from ___ with photopigment ___ and co-neurotransmitters ___ and ___

Answer 10

from IPRGCs
with melanopsin
glutamate, PACAP

Question 11

SCN receives non-photic input from ___ and ___

Answer 11

GHT and raphe nuclei

Question 12

GHT

Answer 12

geniculo-hypothalamic tract

Question 13

IGL

Answer 13

intergeniculate leaflet of thalamus

Question 14

Phenotype of SCN core interneurons: (x2)

Answer 14

VIP, GABA

Question 15

VIP

Answer 15

vasoactive intestinal peptide

Question 16

Primary projection site out from SCN core

Answer 16

to SCN shell

Question 17

Function of SCN core

Answer 17

synchronize intercellular rhythms

Question 18

Efferent phenotype of SCN shell neurons: (x2)

Answer 18

AVP and GABA

Question 19

AVP

Answer 19

arginine vasopressin

Question 20

Primary projections out from SCN shell (x2)

Answer 20

subparaventricular zone (SPVz) and paraventricular nucleus (PVN)

Question 21

SPVz

Answer 21

subparaventricular zone

Question 22

PVN

Answer 22

paraventricular nucleus

Question 23

Result of lesioning SCN in WT mouse

Answer 23

loss of circadian rhythms

Question 24

Result of lesioning SCN and grafting tau mutant SCN

Answer 24

mouse acquires rhythm of donor mouse (20 hours)

Question 25

Which rhythms are and are not re-established by SCN transplant?

Answer 25

Are: locomotor only

Are not: body temp, sleep/wake, hormonal rhythms

Question 26

Light exposure causes [incr./decr.] in melatonin secretion

Answer 26

decrease

Question 27

Core clock genes: (x4)

Answer 27

• Clock
• Bmal1
• Per1/2/3
• Cry1/2

Question 28

key enzyme in molecular clock

Answer 28

CK1d/e (casein kinase I delta/epsilon)

Question 29

Mechanism of molecular clock

Answer 29

1. Clock and Bmal1 promotors enable attach to Per and Cry gene
2. Per and Cry synthesized
3. CK1d/e phosphorylates and degrades Per and Cry
4. Phosphorylated Per/Cry inhibit Clock and Bmal1 promotors, reducing synthesis of additional Per and Cry

Question 30

Mutating PER or CRY results in

Answer 30

changes in period length

Question 31

Mutating BMAL1 or CLOCK results in

Answer 31

loss of rhythmicity

Question 32

Mutating CKIe to increase PER/CRY degradation results in

Answer 32

shortened free-running period