Role of octopamine in walking behavior and sucrose responsiveness
Christine Damrau, Julien Colomb, Björn Brembs
Institut für Neurobiologie, Freie Universität Berlin damrau@zedat.fu-berlin.de
Deutsche Forschungsgemeinschaft
Presented at the XIV European Drosophila Neurobiology Conference in Padua, ITALY, September 2012
Locomotion behavior is different in tßh mutants
Conclusions:
tßh mutants have a deficit in locomotion and fixation behavior. Their walking speed is reduced whereas their stripe fixation is increased.
Walking speed seems to be rescued by yohimbine in mutants and reduced in wild type fed epinastine. That would mean that walking speed may be controlled by both, TA and OA.
Fixation behavior seems to be controlled dosage dependently by OA.
tßh w+
0 4 8 12 16 20
no OA OA dev. YH
Treatment (10mg/ml)
Walking speed [mm/s]
n=8 0
9 18 27 36 45
no OA OA dev.YH
Treatment (10mg/ml)
Stripe deviation [°]
n=8
© redOrbit
0 4 8 12 16
Epi no
Treatment (10mg/ml)
Walking speed [mm/s]
n=4 0
9 18 27 36
Epi no
Treatment (10mg/ml)
Stripe deviation [°]
n=4
Pharmacological Rescue
OA - Octopamine, fed for 3h until test
OA dev. - Octopamine, fed in food during development and for 3h until test
YH - Yohimbine (tyramine receptor blocker), fed for 3h until test
Epi - Epinastine (octopamine receptor blocker), fed for 3h until test
preliminary
tßh mutants:
Decreased speed and increased fixation
T-test, p < 0.004, females 0.0
0.1 0.2 0.3 0.4 0.5 0.6 0.7
tßh w+
Centrophobism for sitting
0 n=16 9 18 27
tßh w+
Stripe deviation [°] *
0 n=16
4 8 12 16
tßh w+
Walking speed [mm/s]
*
n=16
Conclusions:
n~30, females
Sugar motivation is lower in tßh mutants
Genetic background effect
Walking speed [mm/s]
0 4 8 12
16 *
tßh (w+)
Y (CS) CS (CS) Y (w+)
n>30
T-test, p>0.0167, males
0 9 18 27
Stripe deviation [°] *
n>30
tßh (w+)
Y (CS) CS (CS) Y (w+)
0.0 0.1 0.2 0.3 0.4 0.5
Centrophobism for sitting
n>30
tßh (w+)
Y (CS) CS (CS) Y (w+)
1. Trehalose measurement in hemolymph to define OA’s potential role in metabolism
2. TDC2-Gal4 driven rescue of tßh mutation
3. Refining Gal4 rescue in only subsets of these tyraminergic neurons
4. Test OA-receptor mutants
Possible roles of OA in the sugar response process
HUNGER
Response (PER)
OA?
OA? SUGAR
Starvation
OA?
Outlook
n=16
(relative scale) frequence of passsage
>95%
quantile
Transition plots
tßh
CantonS (HS)
n=25
w+ n=16 CantonS (TZ)
n=11
Buridan’s paradigm
HS driven rescue
14 hours 21 hours 0
1 2 3 4 5 6 7
Starvation time
Median (Ʃ responses)
*
0.00.20.40.60.81.0
Sucrose concentration [%]
Mean (PER)
0 0.1 0.3 0.6 1 3 10 30
14 hours 21 hours
40
n>20, CantonS ,females, MWU-Test, p<0.05
Locomotion independent and starvation level sensitive assay to test sugar response
Photo: Jan Rillich
tßh mutants show lower starvation
dependent sucrose response. Therefore we think that OA and/or TA is necessary for sugar motivation.
tßh mutants show prolonged survival.
That could mean that OA and/or TA are involved in metabolic processes.
OA?
tßh w+
0 1 2 3 4 5 6
7 *
Median (Ʃ responses)
tßh mutants are less responsive to
sugar after 20h starvation tßh mutants survive longer when starved to death
tßh w+
0 20 40 60
80 *
LD50 [h]
0.00.20.40.60.81.0
Sucrose concentration [%]
0 0.1 0.3 0.6 1 3 10 30
tßhw+
Mean (PER)
n>45, females, MWU-test, p<0.05 n=16, females, MWU-Test, p<0.05
tßhw+
Proportion surviving 0.00.20.40.60.81.0
Starvation time [h]
0 17 20 23 25 39 42 45 47 49 63 66 70 73 88
Conclusions:
n=16
tßh mutation is semi-dominant
tßh w+ w+/tßh
Stripe deviation [°]
0 9 18 27
Walking speed [mm/s]
0 4 8 12 16
n=13
tßh w+ w+/tßh
n=13
Reproducibility of the phenotype
0 1 2 3 4 5 6
7
May11 June11 July11 Sept11 Okt11 Feb12 Mar12 Apr12 May12
Males tßh w+
Median (Ʃ responses)
16-17 4-5 19-21 11 1-8 4-5 113 23 29
May11 June11 July11 Aug11 Okt11 Mar12 Apr12 May12 0
1 2 3 4 5 6 7
June12 July12 Aug12
Females tßh w+
15-18 3-4 22-23 26 8-10 2-8 23 22-95 114-79 5 33-38 13-19
Sept11
7
0 1 2 3 4 5 6 7
0 0 14 17 20 20 24
morning
afternoon afternoon morning morning afternoon morning afternoon
daytime starvation
Median (Ʃ responses)
tßhw+
Mutant PER phenotype seems to be unstable at 20h of starvation
Wild type:
TYR
TDCTA
TßHOA
Mutant:
TYR
TDCTA
TßHOA
Octopamine synthesis
Introduction
Octopamine acts as a neurohormone, a neuromodulator and a neurotransmitter, contributing to the control of the animal physiology and behavior.
What cellular processes are at play in order to coordinate those different
behaviors?
Benzer, 1967
Wing clipping effect on phototaxis
tßh w+ tßh/w+
0 1 2 3 4 5 6 7
Median (Ʃ responses)
tßh mutation is dominant
* *
n~25, females, MWU-Test, p<0.05 T-test, p>0.0167, males
4T added after each reaction step +50 flies
0 0.02 0.04 0.06 0.08 0.1 0.12
Absorbance (540nm)
Measurement 1 Measurement 2
blank 4T 4G
4T + treatm
4T + 10 f lies
4T + 50 f
lies
10 flies
50 f lies
Measurement of trehalose content in flies
not working so far...
0 0.5 1
Effect index
n=8
tßh w+
0 4 8 12 16
tßh/tßh tßh/+ HStßh/tßh HStßh/+
Walking speed [mm/s]
n=40 a
c
b b
0 9 18 27 36
tßh/tßh tßh/+ HStßh/tßh HStßh/+
Stripe deviation [°]
n=40 a
b
a
a
a
b
a
a a
b
147
