What role does octopamine play in behavioral control in Drosophila?
Christine Damrau 1 , Julien Colomb 1 , Björn Brembs 2
1
Institute for Neurobiology, Freie Universität Berlin
2
Institute for Zoology-Neurogenetics, Universtität Regensburg damrau@zedat.fu-berlin.de, www.lab.brembs.net
Deutsche
Forschungsgemeinschaft
Presented at the 42nd Annual Meeting of the Society for Neuroscience in New Orleans, LA,USA, October 2012
Possible roles of OA in the sugar response process
HUNGER
Response (PER)
OA?
OA? SUGAR
Starvation
OA?
1. Trehalose measurement to calibrate starvation effect
2. Neuron-specific rescue of tßh mutation (cell cluster)
3. Activation and silencing of aminergic neurons
4. Test octopamine and tyramine receptor mutants
Outlook Introduction
tßh mutants have a deficit in locomotion and fixation behavior.
Walking speed may be controlled by a balance between both, tyramine and octopamine since the mutant phenotype can be rescued by giving a tyramine receptor blocker (yohimbine), and induced by an octopamine receptor blocker (epinastine).
Fixation behavior seems to be controlled dosage-dependently by octopamine.
tßh mutants show lower starvation- dependent sucrose responsiveness and prolonged survival while starved to death. Both phenotypes may be explained by an action of the amines on
the metabolic rate.
Interestingly, the tßh loss of function mutation shows dominant effects for
sugar motivation, while having semi-dominant effect on locomotion control.
Conclusions
Possible roles of OA in the sugar response process
HUNGER
Response (PER)
OA?
OA? SUGAR
Starvation
OA?
OA?
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, MWU-Test, p<0.05 (CantonS ,females)
Paradigm to test proboscis extension response (PER)
Photo: Jan Rillich
tßh w+
0 1 2 3 4 5 6
7 *
Median (Ʃ responses)
tßh mutants are less responsive to sugar after 20h starvation
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, MWU-test, p<0.05 (females)
Sugar motivation is lower in tßh mutants
tßh mutants survive longer when starved to death
tßh w+
0 20 40 60
80 *
LD50 [h]
tßh w+
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
n=16, MWU-Test, p<0.05 (females)
tßh mutation is dominant
tßh w+ tßh/w+
0 1 2 3 4 5 6 7
Median (Ʃ responses)
* *
n~25, Kruskal-Wallis, p<0.05 (females)
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?
Flies mutant for the enzyme tyramine-beta-hydroxylase (tßh) have no
octopamine (OA) and a 10-fold increased tyramine (TA) level.
We investigate walking behavior in Buridan’s paradigm and study the proboscis extension response (PER) as a locomotion-independent test for sucrose responsiveness after starvation.
We hypothesize that different subpopulations of octopaminergic neurons are involved in the two different
behaviors.
in Drosophila
OA
Flight
Appetitive learning
Aggression Egg laying
Larval crawling
Sugar motivation Adult locomotion
Sarawasatiet al., 2003 Selcho et al., 2012
Brembs et al., 2007
Schwärzel et al., 2003
Baier, Wittek et al., 2002 Monastiriotiet al., 2003
Sleep
Crocker, Sehgal, 2008
Triglyceride metabolism
Erion et al., 2012
Wild type:
TYR
TDCTA
TßHOA
Mutant:
TYR
TDCTA
TßHOA
Octopamine synthesis
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
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 T-test, p < 0.004, females
Locomotion behavior is different 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<0.017 (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+)
(relative scale) frequence of passsage
>95%
quantile
Transition plots
tßh
CantonS (HS)
n=25
w+ n=16 CantonS (TZ)
n=11
n=16
tßh mutation is semi-dominant
ANOVA, TukeyHSD, p<0.017 (females)
Walking speed [mm/s]
0 4 8 12 16
n=13
tßh w+ w+/tßh
a a
b
tßh w+ w+/tßh
Stripe deviation [°]
0 9 18 27
a
b
a
n=13
tßh w+
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
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
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 approach preliminary
Buridan’s paradigm
Colomb et al., 2012
tßh mutants:
Decreased speed and increased fixation
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
T-test, p<0.004 (females)
Heat shock driven rescue
0 4 8 12 16
tßh tßh/+ HStßh HStßh/+
Walking speed [mm/s]
n=40 a
c
b b
ANOVA, TukeyHSD, p<0.004 (females)
0 9 18 27 36
Stripe deviation [°]
n=40 a
b
a
a
tßh tßh/+ HStßh HStßh/+
0 1 2 3 4 5 6
7
HStßh HStßh tßh
Heat-shocked No heat
Median (Ʃ responses)
preliminary
n~30 (females)
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)
tßh w+
Starvation dependence of sugar response
wild type
n=4 (females)
Heat shock driven rescue
