seasonal regulation

Question 1

effect of constant photoperiod on seasonal rhythms

Answer 1

no effect, seasonal rhythms persist in constant photoperiod

Question 2

why do species near the equator have a circannual rhythm instead of responding to photoperiod

Answer 2

at the equator, there isn’t much change in photoperiod

Question 3

when are circadian rhythms not entrainable

Answer 3

1. day < 20h
2. day > 28h

Question 4

what dictates seasonal physiology

Answer 4

photoperiod

Question 5

when are testes of hamsters vs sheep bigger in size and why

Answer 5

hamsters during summer and sheep during winter because depends on gestation time/reproductive period

Question 6

prolactin secretion in hamsters vs sheep

Answer 6

same pattern of secretion -> winter = low secretion; summer = high secretion

Question 7

what does pineal melatonin rhythm encode

Answer 7

day length information

Question 8

where is melatonin receptor 1 expressed

Answer 8

pars tuberalis (underneath median eminence)

Question 9

what converts t4 to t3

Answer 9

deiodinases2 (DIO2)

Question 10

expression of kiss1 in sheep vs hamsters

Answer 10

sheep = high in winter; hamster = high in summer (inverse seasonal expression)

Question 11

tsh expression in sheep: winter vs summer

Answer 11

summer = expression; winter = no expression

Question 12

tshb expression under long and short days in pars tuberalis

Answer 12

increase in expression during the day (light period)

Question 13

relationship bw eya3 and TSH

Answer 13

eya3 drives tsh

Question 14

eya3 is transcriptionally controlled through (2)

Answer 14

1. e boxes
2. d elements

Question 15

what controls eya3 and how

Answer 15

circadian clock; bmal1/clock binds e boxes on eya3 gene and drives eya3 expression

Question 16

after how long does eya3 stop being suppressed and effects (2)

Answer 16

stops being suppressed after 12h -> if happens to be during dark, eya3 suppressed again; if happens to be during light, activate eya3 and reproductive switch

Question 17

effect of melatonin on eya3

Answer 17

melatonin treatment suppresses eya3

Question 18

what possibly regulates eya3 promoter

Answer 18

camp

Question 19

where is eya3 expressed

Answer 19

pars tuberalis

Question 20

where are season-specific differences in reproductive drive encoded

Answer 20

downstream of DIO2

Question 21

pathway of regulation of seasonal rhythms

Answer 21

clock -> eya3 -> tsh -> t3 & t4 -> kiss1 -> gnrh neurons

Question 22

when do seasonal changes in tsh and dio2 occur

Answer 22

1. photoperiodic changes
2. absence of photoperiodic changes

Question 23

while measuring cage activity, what fluctuated in hamsters under constant light (no photoperiod changes)

Answer 23

body weight and locomotor period (reflection of seasonal timer)

Question 24

rhythmicity of animals living in communities

Answer 24

absence of 24h rhythmicity -> run on endogenous rhythm

Question 25

what happens to rhythm when hamsters exposed to constant light

Answer 25

antiphasic oscillations -> hemispheres in anti-phase

Question 26

what emerges when rats exposed to 22h day

Answer 26

2 locomotor activity rhythms -> desynchrony of vlSCN and dmSCN neurons

Question 27

what rhythm do dat ko mice exhibit in constant darkness

Answer 27

2 rhythmic components (one around 23h another around 27h)

Question 28

per1 in scn of datko mice in constant darkness

Answer 28

normal per1 rhythmicity and staining -> scn cannot account for second rhythmic component

Question 29

effect of drinking water with methamphetamine on rhythmicity in constant darkness

Answer 29

2nd locomotor rhythm component emerges

Question 30

effect of meth on rhythm wo the scn in constant darkness

Answer 30

meth has same effect (2nd rhythm component)

Question 31

characteristics of meth-induced second rhythmic component (2)

Answer 31

1. circadian clock-independent
2. period is variable

Question 32

what other clock exists other than the circadian clock

Answer 32

tunable timing system that can shape sleep:wake rhythmicity and which involves the dopamine system

Question 33

oscillator period of dopaminergic tunable oscillator

Answer 33

2-110h

Question 34

sleep cycle of patients with what disorder resemble mice+meth activity

Answer 34

bipolar disorder

Question 35

what is sleep drifting due to

Answer 35

dissocation bw sleep-wake rhythm and circadian timer (like body temperature)

Question 36

what drives sleep-wake rhythms

Answer 36

usually circadian clock, but also by tunable oscillator involving dopamine system

Question 37

sleep-wake aberrations associated with bpd due to

Answer 37

action of dopaminergic oscillator system