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Flashcards in 36-CircadionRhythms Deck (32)
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1

circadian rhythm

cycle with period of approx. 24 hours

2

zeitgeber

"time giver" (e.g. light/dark)

3

FRP

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

4

SCN

suprachiasmatic nucleus

5

SCN located at base of ___ overlying ___

hypothalamus, optic chiasm

6

PER2

clock gene

7

SCN receives direct input from ___

retina

8

RHT

retino-hypothalamic tract

9

IPRGCs

intrinsically photosensitive retinal ganglion cells

10

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

from IPRGCs
with melanopsin
glutamate, PACAP

11

SCN receives non-photic input from ___ and ___

GHT and raphe nuclei

12

GHT

geniculo-hypothalamic tract

13

IGL

intergeniculate leaflet of thalamus

14

Phenotype of SCN core interneurons: (x2)

VIP, GABA

15

VIP

vasoactive intestinal peptide

16

Primary projection site out from SCN core

to SCN shell

17

Function of SCN core

synchronize intercellular rhythms

18

Efferent phenotype of SCN shell neurons: (x2)

AVP and GABA

19

AVP

arginine vasopressin

20

Primary projections out from SCN shell (x2)

subparaventricular zone (SPVz) and paraventricular nucleus (PVN)

21

SPVz

subparaventricular zone

22

PVN

paraventricular nucleus

23

Result of lesioning SCN in WT mouse

loss of circadian rhythms

24

Result of lesioning SCN and grafting tau mutant SCN

mouse acquires rhythm of donor mouse (20 hours)

25

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

Are: locomotor *only*
Are not: body temp, sleep/wake, hormonal rhythms

26

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

decrease

27

Core clock genes: (x4)

-Clock
- Bmal1
- Per1/2/3
- Cry1/2

28

key enzyme in molecular clock

CK1d/e (casein kinase I delta/epsilon)

29

Mechanism of molecular clock

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

30

Mutating PER or CRY results in

changes in period length