Cohen Target Receptors in the Control of Insect Pests: Part II

1. Auflage 2014
ISBN: 978-0-12-417171-8
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, Band Volume 46, 520 Seiten

Reihe: Advances in Insect Physiology

This volume of Advances in Insect Physiology contains comprehensive interdisciplinary reviews on basic and practical aspects relevant to major target receptors for crucial physiological functions and mechanisms in prokaryotic and eukaryotic organisms, particularly insects. Chapters emphasize advanced genomic, molecular biology, chemical, and proteomic research on the receptors and their corresponding agonist and antagonist ligands. The book encompasses target systems such as sodium channels, octopamine/tyramine receptors, ABC transporters, acetylcholinesterase as a target enzyme, juvenile hormone receptors, and receptors targeted by neuropeptides. - Contains important, comprehensive and in-depth reviews - An essential reference source for invertebrate physiologists and neurobiologists, entomologists, zoologists, and insect biochemists - First published in 1963, this serial is ranked second in the highly competitive ISI category of Entomology

Autoren/Hrsg.

Cohen, Ephraim

Leseproben

Chapter Two

Molecular Signalling, Pharmacology, and Physiology of Octopamine and Tyramine Receptors as Potential Insect Pest Control Targets

Hiroto Ohta*; Yoshihisa Ozoe†    * Graduate School of Science and Technology, Kumamoto University, Kumamoto, Japan
† Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane, Japan

Abstract

Octopamine (OA) and tyramine (TA) are phenolamines that are synthesised from tyrosine and are widely distributed in insects. These amines play vital roles as neurotransmitters, neuromodulators, and neurohormones in a wide variety of physiological processes in insects. G protein-coupled receptors (GPCRs) mediate the signal transduction of OA and TA by modifying intracellular Ca2 + and cAMP levels. Since the first discovery of a phenolamine GPCR, two main types of OA GPCRs and three types of TA GPCRs have been revealed by studies of various insect species over the past two decades. The OA receptors have been studied as targets of classical amidine acaricide/insecticides, even though these GPCRs are not well understood at the molecular level; however, new discoveries have recently provided more information regarding these GPCRs. This chapter reviews the recent progress that has been made in the understanding of the molecular signalling, pharmacology, and physiology of OA and TA GPCRs, which may lead to the increased study of OA and TA GPCRs as insect pest control targets.

Keywords

Biogenic amine

G protein-coupled receptors

Octopamine

Octopamine receptors

Targets for insect pest control

Tyramine

Tyramine receptors

Abbreviations

CaMKII Ca2 +/calmodulin-dependent protein kinase II

CDM chlordimeform

CHO Chinese hamster ovary

CRE cAMP response element

CS conditioned stimulus

DA dopamine

DMCDM demethylchlordimeform

dTDC Drosophila tyrosine decarboxylase

GPCR G protein-coupled receptor

HEK human embryonic kidney

HTS high-throughput screening

IP3 inositol 1,4,5-triphosphate

MB mushroom body

NC-5 2-(2,6-diethylphenylimino)imidazolidine

OA octopamine

OAaR a-adrenergic-like OA receptor

OAßR ß-adrenergic-like OA receptor

PER proboscis extension reflex

PLCß phospholipase C-ß

QMP queen mandibular pheromone

SOG subesophageal ganglion (or ganglia)

TA tyramine

TAR1 tyramine receptor 1

TAR2 tyramine receptor 2

TAR3 tyramine receptor 3

TBH tyramine ß-hydroxylase

TDC tyrosine decarboxylase

TH tyrosine hydroxylase

TM transmembrane domain

US unconditioned stimulus

VMAT vesicular monoamine transporter

VUM ventral unpaired median

1 Introduction

Octopamine (OA) and tyramine (TA) are closely related phenolamines that are derived from the amino acid tyrosine (Fig. 2.1). OA is a biogenic amine that is involved in various vital central and peripheral physiological processes in invertebrates, including insects. TA is a precursor for the biosynthesis of OA, but it has also been established as an independent bioactive amine (Lange, 2009). In some respects, these phenolamines may be considered the invertebrate counterparts of the catecholamines adrenaline and noradrenaline in vertebrates because of their structural and physiological resemblance.

Figure 2.1 Synthesis of TA, OA, and dopamine (DA). TDC, tyrosine decarboxylase; TBH, TA ß-hydroxylase; TH, tyrosine hydroxylase; DDC, DOPA decarboxylase; DADH, DA dehydroxylase.

OA and TA function as neurotransmitters, neuromodulators, and neurohormones. Physiological responses are elicited by the binding of OA and TA to specific G protein-coupled receptors (GPCRs), which triggers molecular signalling via G proteins, effectors, and second messengers. OA receptors have been extensively studied as targets of insecticides, such as chlordimeform (CDM) and amitraz (Fig. 2.2) (Hollingworth and Lund, 1982; Hollingworth et al., 1984; Knowles, 1982; Matsumura and Beeman, 1982), and remain a promising target for novel insect pest control agents (Casida and Durkin, 2013). In contrast, few studies have been performed on TA receptors from the perspective of insecticidal targets.

Figure 2.2 Chemical structures of CDM and amitraz.

OA was first identified in the salivary gland of an octopus in 1952 (Erspamer, 1952). Over the last 60 years, a plethora of information regarding the physiology and pharmacology of OA, TA, and their receptors has accumulated. Rapid progress in biogenic amine research has recently been made using advanced technologies, including the cloning, silencing, and overexpression of genes of interest. Important progress has been made over the past two decades as the presence of multiple types of OA and TA receptors has been revealed by genome sequence analyses, cloning, and heterologous expression of the encoding cDNAs from several insect species. Their molecular functions, signalling pathways, and pharmacology have since been studied as well.

This chapter provides an overview of the recent progress that has been made in the physiological and pharmacological studies of OA and TA receptors in the context of insect pest control. This chapter does not intend to cover all aspects of OA and TA research. Rather, it focuses on the classification of receptors that have been isolated from insect species to date and describes what is known about the signalling pathways, the specific agonists and antagonists, and the physiological responses for each of the receptor classes. For information regarding earlier studies and topics that are not covered here, the readers may refer to several excellent reviews (Blenau and Baumann, 2001; David and Coulson, 1985; Evans, 1980; Evans and Maqueira, 2005; Farooqui, 2007, 2012a,b; Lange, 2009; Monastirioti, 1999; Orchard et al., 1993; Pflüger and Stevenson, 2005; Robertson and Juorio, 1976; Roeder, 1994, 1999, 2005; Roeder et al., 2003; Stevenson and Spörhase-Eichmann, 1995; Stevenson et al., 2005; Verlinden et al., 2010a).

2 OA and TA

Both OA and TA are synthesised from tyrosine, an aromatic amino acid. Decarboxylation of tyrosine by tyrosine decarboxylase (TDC) produces TA, which is then hydroxylated at the ß-position of its side chain by tyramine ß-hydroxylase (TBH) (Cole et al., 2005; Monastirioti et al., 1996) to yield OA (Fig. 2.1). Two TDCs have been isolated from the fruit fly Drosophila melanogaster; one TDC (dTDC1) is expressed in nonneural tissues and the other TDC (dTDC2) is expressed in neural tissues (Cole et al., 2005). TA has a structural resemblance to dopamine (DA), which differs only in the presence of an m-hydroxyl group on the benzene ring (Fig. 2.1).

Given that OA has a chiral carbon, substantial attention has been focused on determining which enantiomer is the naturally occurring isomer (Fig. 2.1). The D(-)-isomer is the naturally occurring isomer in various insects (Blau et al., 1994; Goosey and Candy, 1980a,b; Starratt and Bodnaryk, 1981) and is more potent or more efficacious than the L(+)-isomer against the native OA receptors of various insect species (Dougan and Wade, 1978; Evans et al., 1988; Harmar and Horn, 1977; Roberts and Walker, 1981; Whim and Evans, 1988). The (-)-isomer was determined to have an R absolute configuration on the basis of the superimposability of the circular dichroism (CD) spectrum of (-)OA on the CD spectrum of (-)synephrine, the absolute configuration of which was determined by X-ray crystallography (Midgley et al., 1989). (R)(-)-OA was shown to be more potent than (S)(+)-OA in signal transduction in two types of silkworm (Bombyx mori) OA receptors that were stably expressed in human embryonic kidney (HEK)-293 cells (Chen et al., 2010; Huang et al., 2008; see Section 4.3).

3 Molecular...