The Effect Of Deltamethrin On Zebrafish Behavior And The Expression Of M3 And M5 Receptors

With the continuous development of our economy and agriculture,there are various kinds of pollution,especially water pollution.Faced with severe challenges,more and more people have begun to devote themselves to the study of water pollution and water quality monitoring,early warning and assessment.It is reported that the changes in fish behavior are the most sensitive indicators of contaminants and can be used for water quality warnings.At the same time,the behavioral changes are regulated by internal mechanisms.Acetylcholine?ACh?specifically acts on cholinergic receptors,activates the coupled receptors,and different signaling pathways in the organism are activated,leading to different biological effect.For example,changes in biological behavior,etc.Under the environmental stress,the life and survival of the organism are threatened,the external behavior changes accordingly,the internal physiological and biochemical indicators also change,and there may be a certain correlation between the behavior of the organism and the cholinergic receptors.In this paper,the changes of behavioral strength of zebrafish exposed to low concentrations of cadmium chloride?CdCl₂?,deltamethrin?DM?,atrazine?ATZ?and disodium hydrogen phosphate?Na₂HPO₄?were studied.The study found that neurological drugs such as deltamethrin have a greater toxic effect on zebrafish.Therefore,in the subsequent study on the relationship between the relative expression of muscarinic receptors?M3b,M5a,M5b?in muscle and eye and behavioral effects under the environmental stress,deltamethrin was continuously selected as a contaminant.RT-PCR was used in the study of changes in the expression of muscarinic receptors in zebrafish.Among them,the median lethal concentration of deltamethrin to zebrafish 48h measured by the laboratory was set as one toxic unit?1TU?.The aim is to combine the external behavioral changes of organisms with the intrinsic physiological and biochemical changes under the environmental stress,to explain the changes in organisms in many aspects,and to enrich the indicators of water quality monitoring,determine the existence of pollution and predict its harm.The specific findings are as follows:1.In the study of the behavioral changes of zebrafish by different drugs,we found that the behavioral strength of zebrafish in the four different treatment groups changed differently,and the average value was lower than that of the control group,which was inhibited to varying degrees.In the observation,we found that the behavior of zebrafish showed obvious circadian rhythm,and the rhythm disorder occurred,and there was a delay phenomenon,among which the effect of deltamethrin was the most significant.Therefore,in the subsequent experiments of receptor expression and behavioral changes,we continued to use deltamethrin for experiments.2.Under the exposure of 168 h deltamethrin?0.1 TU and 10%surface water concentration?,not only the behavior of zebrafish was similar to that of the previous pre-experiment,and a dose effect phenomenon appeared.Moreover,the expression of different subtypes of muscarinic receptors in zebrafish muscle has also been affected to varying degrees,and there may be a dose effect relationship.The change in relative expression of muscle in 0.1TU exposure showed that the relative expression level fluctuated greatly in the first three days of exposure,and it stabilized in the later stage,especially M3b,and the relative expression of the receptor in the night stage was higher than that in the daytime.This is consistent with the rhythmic studies found in the cholinergic system.In the inactive period of 24:00-8:00 after the zebrafish behavior was delayed for 3 h,the relative expression of receptors in most stages was relatively high,especially at the concentration of0.1 TU.The relative expression levels of the three subtypes during this period were higher than the active period.According to the experimental results,it is speculated that M3 plays a major role in coordinating muscle movement,and other subtype receptors also play a certain auxiliary role,which together regulate the behavioral changes of zebrafish,and further research is needed in future experiments.3.The muscarinic receptor subtype expressed in the zebrafish eye showed significant rhythm in two different concentrations of exposure,especially M5a.However,the 10%surface water concentration has a greater impact than 0.1TU,there is a certain dose effect relationship.The effect of the eye was earlier than that of the muscle,and its relative expression at 0.5 h increased sharply due to drug stimulation,0.5 h earlier than the muscle.The expression of M5 in the eye is involved in the regulation of the open photoreceptor of the rhythmic axis,in synergy with the M3 receptor involved in the operation between the eye clock and the central clock.They regulate the circadian rhythm in the body,which in turn regulates the rhythm of the biological activity.The change in the relative expression levels of M3 and M5 at two different concentrations of deltamethrin provides a possibility for the interpretation of the behavioral rhythm disorder,and according to the experimental results,the M5a may play a greater role.In conclusion,deltamethrin,a neurological drug,has a certain toxic effect on the behavior of zebrafish and the relative expression of its receptor,and has a dose effect relationship.And deltamethrin affects the changes in the relative expression of intrinsic receptors and the activity of acetylcholinesterase,which in turn affects external behavioral changes and rhythmic disorders.Among them,M3 and M5 receptors play an important role in it.At the same time,the effects of behavior are not only affected by the cholinergic system,but also accompanied by the regulation of the nervous system and the participation of other circadian clock mechanisms,which need to be further studied in future experiments.