Practical report: PSY236 Student: Studentid:
PSY236 (Biopsychology and Learning), Practical 1
The effect of methamphetamine on aggressive behaviour in crickets Abstract
Our experiment aims to examine the potential of methamphetamine to elicit
aggressive behaviour in crickets. It seems to be reasonable to assume that
methamphetamine makes crickets more aggressive, because it has been shown that
methamphetamine increases aggression in various species, including humans
(Sekine et al., 2006). Methamphetamine is known to reverse the dopamine
(Kuczenski, Segal, Cho, & Melega, 1995) and serotonine transporters (Kokoshka et
al., 1998), resulting in an increase of neurotransmitters in the synaptic cleft. Since in
particular dopamine is said to be involved in aggressive behaviour (Louilot et al.,
1986), it seems justified to assume that methamphetamine increases the level of
aggression in crickets, too. It will turn out that our experiment is not able to provide
Neurotransmitters play a substantial role in behaviour. All types of behaviour are
linked to a characteristic chemical profile in the brain. Even minor changes in the
composition of neurotransmitters can lead to a variety of behavioural changes. One
of the fundamental types of neurotransmitters are monoamines, such as dopamine,
serotonin, noradrenaline, adrenaline, histamine and octopamine. Since monoamines
are involved in many processes of neurotransmission, they are highly influential with
In this paper, we will examine the role of specific neurotransmitters in the
behaviour of crickets (acheta domestica). In the nervous system of crickets, the
monoamines octopamine, serotonine and dopamine are essentially important (Nagao
& Tanimura, 1988). Hence, it is necessary to bring these chemicals into sharper
More specifical y, we want to investigate the effects of metamphetamine on
cricket behaviour. For other species, it has been shown that methamphetamine
promotes aggressive behaviour. Studies have provided evidence in the case of, for
example, humans (Sekine et al., 2006; Pinhey & Wel s, 2007) and mice (Sokolov,
Schindler, & Cadet, 2004; Sokolov & Cadet, 2006).
This phenomenon can be explained from the neurochemical perspective of
neurotransmitters: Methamphetamine is able to reverse the dopamine transporters at
the presynaptic terminals (Kuczenski, Segal, Cho, & Melega, 1995; Fumagal i,
Gainetdinov, Valenzano, & Caron, 1998). Usually, after an action potential has
caused dopamine neurotransmission and a postsynaptic potential has been created,
the dopamine transporter takes up dopamine from the synaptic cleft. This is
necessary due to various various: First, the dopamine has finished its task, namely
creating a single EPSP. Hence, it has to be removed from the synaptic cleft, away
from the receptors at the postsynapses. Second, the dopamine transporter moves
dopamine into the presynaptic terminals so that it can be metabolised or repackaged
into vesicles again. This is much more economic and efficient compared to the
creation of new dopamine for each process of neurotransmission. But when
methamphetamine reverses the dopamine transporter, these tasks can not be
executed – the dopamine reuptake is blocked. Thus, dopamine stays in the synaptic
cleft. Furthermore, since the dopamine transporter is reversed and not only blocked,
it also moves stored dopamine from the presynaptic terminal to the synaptic cleft.
These processes directly lead to a greater postsynaptic effect. There is also evidence
that methamphetamine reverses the serotonin transporter (Kokoshka et al., 1998;
Haughey, Fleckenstein, Metzger, & Hanson, 2000; Sekine at al., 2006), resulting in
an increase of the postsynaptic effect of serotonin, respectively.
The next step is to tie this neurochemical modification to a change in behaviour.
It has been shown that an increase in dopamine causes a higher level of aggression
in many species (Louilot et al., 1986; Glazer & Dickson, 1998; Fitzgerald, 1999).
However, there are contradictory studies with respect to serotonin. Some research
suggests that serotonin plays a role in aggressive behaviour for various species
(Unis et al., 1997, Chiavegatto & Nelson, 2003; Donly & Caveney, 2005), including
crickets (Murakami & Itoh, 2003). But other studies indicate evidence that the
opposite is the case (Yodyingyuad et al., 1985; Volavka et al., 1990).
Although the role of serotonin is not yet clear-cut, there is converging evidence in
the case of dopamine. Since both serotonin and dopamine are present in the nervous
system of crickets, we assume that methamphetamine encourages aggressive
behaviour in crickets. The aim of this paper is to test this hypothesis. Materials and Methods
In our experiment, we examined adult male crickets (acheta domestica). They were
obtained from Biosupplies NSW and housed in a plastic tube with 24 other crickets.
The crickets were supplied by means of soaked carrots and a damp sponge.
The experimental procedure was the following: First of al , a cricket (“resident”)
was put into a 2 litre round glass container. After 20 minutes, another cricket
(“intruder”) was injected with either 20 µl of saline (0.9%, control group) or 1 mg/ml of
methamphetamine (dissolved in saline) into the abdomen of the cricket by means of
a 29 Ga hypodermic needle and 1 ml syringe. Saline was purchased from the Clifford
Hallam Pharmaceuticals NSW and Methamphetamine from the Australian
Government Analytical Laboratories NSW. 10 minutes after the treatment, the
intruder was put into the contrainer to the resident. Thereafter, we observed their
behaviour for 15 minutes, namely the horizontal locomotor activity. Since we
intended to measure the aggressive behaviour, we focussed on 3 features, each
measured by a different person: First, we measured the total time of aggressive
behaviour with the use of a digital stopwatch. We defined aggressive behaviour by
antennal fencing, unilateral and bilateral mandible spreading, mandible engagement,
grappling, chirping and kicking. Second, we counted the number of chirrups. The last
feature we measured was the number of kicks. For each of these features, we did not
only measure the overal results, but also the data for each minute.
Our data contained 34 cricket pairs for the control group and 37 cricket pairs for
the methamphetamine treatment. Al crickets were naïve to this experiment and the
resident and intruder have never interacted with each other before. The lighting was
at a moderate level and we tried to lower noise. For the statistical analysis, we
applied an unpaired t-test for each feature using the software SPSS.
The results turned out to be not significant. This holds for aggression time (p=0,895),
chirrups (p=0,139) and kicks (p=0,115). The mean of the aggression time was 100
seconds for saline, with a standard error of 15,419s, and 97,46s for
methamphetamine, with a standard error of 11,705s. For chirrups, the means were
183,62s for saline (SEM=41,294s) and 112,86s for methamphetamine
(SEM=24,699s), for kicks it was 23,38s for saline (SEM=6,026s) and 13,32s for
The results show that our treatment with methamphetamine did not change the
aggressive disposition of crickets, which is contrary to our initial hypothesis. There
are various reasons which could have played a role in this outcome.
One reason could be that the experiment was simply not properly executed,
since the data was measured mostly by unexperienced students. In addition to that,
some unintended factors could have influenced the result. For example, some
crickets were missing a leg and some cricket pairs differed considerably in size.
But there are also many conceivable neurological reasons. Our hypothesis was
mainly driven by the effect of methamphetamine on the dopamine transporter.
However, it has been shown that dopamine is present to a lesser extent than
octopamine and serotonin in the cricket nervous system (Nagao & Tanimura, 1988).
Hence, dopamine is possibly not very influential on cricket behaviour. Studies
suggest that octopamine is more important than dopamine when it comes to
aggressive behaviour in crickets (Stevenson, Dyakonova, Ril ich, & Schildberger,
2005; Adamo, Linn, & Hoy, 1995). The higher the level of octopamine, the higher the
level of aggression. This relationship has also been shown for other insects (Zhou,
Rao, & Rao, 2008). But there is, at least to my knowledge, no clear evidence that
methamphetamine significantly increases the level of octopamine in crickets.
Octopamine is often called the noradrenaline for invertebrates. For vertebrates, it has
been shown that methamphetamine increases noradrenaline (Ferrucci et al., 2007),
which is involved in aggressive dispositions – but evidence for an analogous increase
of octopamine in invertebrates seems to be lacking. Hence, the role of octopamine
could be the crucial factor for the results of our experiment.
Furthermore, some research indicates that serotonine transporters have a lower
sensitivity for trycyclic antagonists in some insects (Donly & Caveney, 2005). Maybe
this phenomenon also applies to crickets. In that case, the influence of serotonin
would be decreased. Moreover, it has been shown that GABA and glutamate are
involved in aggressive behaviour of vertebrates as well (Puglisi-Allegra et al., 1979;
Miczek et al. 2004). It is possible that the effects of these chemicals affected the
results of our experiment, in a way which we did not expect.
Another good reason for the outcome of our experiment could be the fact that we
only measured a singular treatment with methamphetamine. It is reasonable to
assume that the results of a long-term treatment with methamphetamine would have
been different. In mice (Landa, Slais, & Culcova, 2006) and monkeys (Melega et al.,
2008), a singular treatment with methamphetamine increases aggressive behaviour
and long-term treatment with methamphetamine decreases the level of aggression.
Maybe the opposite is true for invertebrates like crickets. A change in the number of
transporters due to an adaptation could play a role.
Apart from that, it may be the case that the applied dosage of methamphetamine
was not appropriate. There is evidence that a low dosage and a high dosage can
have contrary effects with respect to aggressive dispositions (Kuczenski, Segal, Cho,
Melega, 1995). There is evidence for this phenomenon in the case of rats (Silverman,
1966a) and cats (Hoffmeister & Wuttke, 1969).
We can conclude that there is a broad spectrum of conceivable explanations for
the results of our experiment. Experiments with locusts or cockroaches may offer
further insights, since their neurochemical profile is similar to the cricket (Nagao &
Tanimura, 1988). It has to be the object of further research to determine the precise
effects of methamphetamine on the cricket nervous system. References
Adamo, S. A., Linn, C. E., & Hoy, R. R. (1995). The role of neurohormonal
octopamine during 'fight or flight' behaviour in the field cricket Gryllus bimaculatus. J
Chiavegatto, S. & Nelson, R. J. (2003). Interaction of nitric oxide and serotonin in
aggressive behavior. Horm Behav 44, 233–241.
Donly, B. C. & Caveney, S. (2005). A transporter for phenolamine uptake in the
arthropod cns. Archives of Insect Biochemistry and Physiology 59, 172-183.
Ferrucci, M., Busceti, C. L., Nori, S. L., Lazzeri, G., Bovolin, P., Falleni, A.,
Mastroiacovo, F., Pompili, E., Fumagal i, L., Paparelli, A., & Fornai, F. (2007).
Methamphetamine induces ectopic expression of tyrosine hydroxylase and increases
noradrenaline levels within the cerebellar cortex. Neuroscience 149(4), 871-884.
Fitzgerald, P. (1999). Long-acting antipsychotic medication, restraint and treatment in
the management of acute psychosis. Aust N Z J Psychiatry 33, 660–666.
Fumagal i, F., Gainetdinov, R. R., Valenzano, K. J., & Caron, M. G. (1998). Role of
dopamine transporter in methamphetamine-induced neurotoxicity: evidence from
mice lacking the transporter. J Neurosci 18(13), 4861-4869.
Glazer, W. M. & Dickson, R. A. (1998). Clozapine reduces violence and persistent
aggression in schizophrenia. J Clin Psychiatry 59(3), 8–14.
Haughey, H. M., Fleckenstein, A. E., Metzger, R. R., & Hanson, G. R. (2000). The
effects of methamphetamine on serotonin transporter activity: role of dopamine and
hyperthermia. J Neurochem 75(4), 1608-1617.
Hoffmeister, F. & Wuttke, W. (1969). On the actions of psychotropic drugs on the
attack- and aggressivedefensive behaviour of mice and cats. Aggressive Behaviour,
Kokoshka, J. M., Metzger, R. R., Wilkins, D. G., Gibb, J. W., Hanson, G. R., &
Fleckenstein, A. E. (1998). Methamphetamine treatment rapidly inhibits serotonin,
but not glutamate, transporters in rat brain. Brain Research 799(1), 78-83.
Kuczenski, R., Segal, D. S., Cho, A. K., & Melega, W. (1995). Hippocampus
norepinephrine, caudate dopamine and serotonin, and behavioral responses to the
stereoisomers of amphetamine and methamphetamine. J Neurosci 15, 1308-1317.
Landa, L., Slais, K., & Sulcova, A. (2006). Impact of cannabinoid receptor ligands on
behavioural sensitization to antiaggressive methamphetamine effects in the model of
mouse agonistic behaviour. Neuro Endocrinol Lett 27(6), 703-710.
Louilot, A., Le Moal, M., & Simon, H. (1986). Differential reactivity of dopaminergic
neurons in the nucleus accumbens in response to different behavioral situations. An
in vivo voltammetric study in free moving rats. Brain Research 397, 395–400.
Melega, W. P., Jorgensen, M. J., Lacan, G., Way, B. M., Pham, J., Morton, G., Cho,
A. K., Fairbanks, L. A. (2008). Long-term methamphetamine administration in the
vervet monkey models aspects of a human exposure: brain neurotoxicity and
behavioral profiles. Neuropsychopharmacology 33(6), 1441-1452.
Miczek, K. A., Faccidomo, S., De Almeida, R. M., Bannai, M., Fish, E. W., DeBold, J.
F. (2004). Escalated aggressive behavior: new pharmacotherapeutic approaches and
opportunities. Ann N Y Acad Sci 1036, 336–355.
Murakami, S. & Itoh, M. T. (2003). Removal of both antennae influences the
courtship and aggressive behaviors in male crickets. J Neurobiol 57(1), 110-118.
Nagao, T. & Tanimura, T. (1988). Distribution of biogenic amines in the cricket
central nervous system. Analytical Biochemistry 171, 33-40.
Pinhey, T. K. & Wel s, N. R. (2007). Asian-Pacific Islander adolescent
methamphetamine use: does ice increase aggression and sexual risks?. Substance use & misuse 42(11), 1801-1809.
Puglisi-Allegra, S., Mack, G., Oliverio, A., Mandel, P. (1979). Effects of apomorphine
and sodium di-n-propylacetate on the aggressive behaviour of three strains of mice.
Prog Neuro-Psychopharmacol 3, 491–502.
Sekine, Y., Ouchi, Y., Takei, N., Yoshikawa, E., Nakamura, K., Futatsubashi, M.,
Okada, H., Minabe, Y., Suzuki, K., Iwata, Y., Tsuchiya, K. J., Tsukada, H., Iyo, M., &
Mori, N. (2006). Brain serotonin transporter density and aggression in abstinent
methamphetamine abusers. Arch Gen Psychiatry 63(1), 90-100.
Silverman, A. P. (1966a). The social behaviour of laboratory rats and the action of
chlorpromazine and other drugs. Behaviour 27, 1-38.
Sokolov, B. P., Schindler, C. V., & Cadet, J. L. (2004). Chronic methamphetamine
increases fighting in mice. Pharmacology, biochemistry and behavior 77(2), 319-326.
Sokolov, B. P. & Cadet, J. L. (2006). Methamphetamine causes alterations in the
MAP kinase-related pathways in the brains of mice that display increased
aggressiveness. Neuropsychopharmacology 31(5), 956-966.
Stevenson, P. A., Hofmann, H. A., Schoch, K., & Schildberger, K. (2000). The fight
and flight responses of crickets depleted of biogenic amines. J Neurobiol 43(2),
Stevenson, P. A., Dyakonova, V., Rillich, J., & Schildberger, K. (2005). Octopamine
and experience-dependent modulation of aggression in crickets. J Neurosci 25(6),
Volavka, J., Crowner, M., Brizer, D., Convit, A., Van Praag, H., Suckow, R. F. (1990).
Tryptophan treatment of aggressive psychiatric inpatients. Biol Psychiatry 28, 728–
Yodyingyuad, U., De la Riva, C., Abbott, D. H., Herbert, J., Keverne, E. B. (1985).
Relationship between dominance hierarchy, cerebrospinal fluid levels of amine
transmitter metabolites (5-hydroxyindole acetic acid and homovanil ic acid) and
plasma cortisol in monkeys. Neuroscience 16, 851–858.
Unis, A. S., Cook, E. H., Vincent, J. G., Gjerde, D. K., Perry, B. D., Mason, C., &
Mitchell, J. (1997). Platelet serotonin measures in adolescents with conduct disorder.
Biol Psychiatry 42, 553–559.
Zhou, C., Rao, Y., & Rao, Y. (2008). A subset of octopaminergic neurons are
important for Drosophila aggression. Nature Neuroscience 11(9), 1059-1067.
Tables and Figures
This graph shows the mean of the total aggression time (for 15 minutes of
experimental procedure) in seconds for both the saline and the methamphetamine
) in 5m s/1 e (
One can see that both the mean of the total aggression time as well as the standard
error of the mean are slightly higher for saline than for mehtamphetamine. However,
this result has turned out to be not significant.
This graph shows the mean of the aggression time in seconds for each minute of the
experiment (non-cumulative) for both the saline and the methamphetamine
s/m e ( im T ressio g g A Time (min)
One can see that the values for both treatments are varying, with neither of them
being constantly higher than the other. Both the minimum as well as the maximum
aggression time per minute can be found in the results for the methamphetamine
treatment: 4s at minute 6 and 9s at minute 5. The SEM results do not seem to show
This graph shows the mean of the total number of chirrups (for 15 minutes of
experimental procedure) for both the saline and the methamphetamine treatment. ) in 5m 150 er/1 b m u n s ( p ru ir h 100 tal C o T
One can see that both the mean of the total number of chirrups as well as the SEM
are higher for saline than for mehtamphetamine. However, this result has turned out
This graph shows the mean of the number of chirrups for each minute (non-
cumulative) for both the saline and the methamphetamine treatment. ) in 15 er/m b m u n s ( p ru ir 10 Time (min)
One can see that both the means of the number of chirrups per minute and the SEM-
values are always higher for saline than for methamphetamine. In addition to that, the
means of the number of chirrups per minute seem to be constantly increasing,
although there are some breaks (mostly for saline at minutes 7 and 13). Saline takes
the maximum of 17 at minute 11 and methamphetamine takes the minimum of 5 at
This graph shows the mean of the total number of kicks (for 15 minutes of
experimental procedure) for both the saline and the methamphetamine treatment. er/1 b m u n
One can see that both the mean of the total number of kicks as well as the SEM are
higher for saline than for mehtamphetamine. However, this result has turned out to
This graph shows the mean of the number of kicks for each minute (non-cumulative)
for both the saline and the methamphetamine treatment. Time (min)
One can see that both the means of the number of kicks per minute are similar for
both treatments until minute 7. However, from that minute on, the values for saline
are clearly increasing whereas the values for methamphetamine are decreasing. This
gap gets balanced again at the end of the experiment. The SEM-results are mostly
higher for saline than for methamphetamine. Saline takes the maximum of 2 kicks
per minute and methamphetamine the minimum of 0 kicks per minute – this holds for
This table shows the results of the independent samples t-test from the statistics
software SPSS. The tested for the variables total aggression time, total number of
Group Statistics Independent Samples Test
Data Roaming Service Coverage and Tariff Updated Since 10 Oct 2013 Minimum Charge Unit Thereafter Charge Destination Network Code Charges (HK$/KB) Unit (KB) 收費 ( 港幣 $/KB) Data Roaming Service Coverage and Tariff Updated Since 10 Oct 2013 Minimum Charge Unit Thereafter Charge Destination Network Code Charges (HK$/KB) Unit (KB) 收�
Kvalitet i strålskyddsarbetet, 3-5 februari 2004 Strålskydd och kvalitetssäkring i ett ekonomiskt perspektiv Magnus Halin Fortum Power and Heat, Generation, Lovisa kraftverk Rubriken Strålskydd och kvalitetssäkring i ett ekonomiskt perspektiv ger möjlighet att betrakta nämnda faktorer ur olika synvinklar. I dagens läge betyder det ekonomiska perspektivet oftast att arbetet/verk