Pharmacological Properties of the Type 1 Tyramine Receptor in the Diamondback Moth, Plutella xylostella

Abstract

Tyramine receptors (TARs) can be activated by tyramine (TA) or octopamine (OA) and have been shown to be related to physiological regulation (e.g., gustatory responsiveness, social organization, and learning behavior) in a range of insect species. A tyramine receptor gene in Plutella xylostella, Pxtar1, was cloned and stably expressed in the HEK-293 cell line. Pharmacological properties and expression profile of Pxtar1 were also analyzed. Tyramine could activate the PxTAR1 receptor, increasing the intracellular Ca2+ concentration ((Ca2+)i) at an EC50 of 13.1 nM and reducing forskolin (10 μM)-stimulated intracellular cAMP concentration ((cAMP)i) at an IC50 of 446 nM. DPMF (a metabolite of amitraz) and L(-)-carvone (an essential oil) were found to act as PxTAR1 receptor agonists. Conversely, yohimbine and mianserin had significant antagonistic effects on PxTAR1. In both larvae and adults, Pxtar1 had the highest expression in the head capsule and expression of Pxtar1 was higher in male than in female reproductive organs. This study reveals the temporal and spatial differences and pharmacological properties of Pxtar1 in P. xylostella and provides a strategy for screening insecticidal compounds that target PxTAR1.

The Insect Type 1 Tyramine Receptors: From Structure to Behavior

“…Similar results, i.e., yohimbine > mianserin > phentolamine > chlorpromazine, were obtained when investigating the P. xylostella TAR1 expressed in HEK 293T cells [ 47 ]. When biogenic amines different from TA and OA, such as dopamine, adrenaline, noradrenaline, L-DOPA, and histamine, were tested on TAR1s, no significant agonist effects were observed, suggesting that this receptor class is selectively responsive to TA and OA [ 40 , 42 , 44 , 45 , 46 , 47 ]. The pharmacological profile of TAR1 has been characterized especially for the antagonist, whereas our knowledge of alternative agonists is almost completely lacking.…”

Transcriptomic analysis to elucidate the response of honeybees (Hymenoptera: Apidae) to amitraz treatment

“…STKs participate in stress resistance in insects [51]. In honeybees, STKs are related to cold and heat stress [52,53]. Herein, we found that the expression levels of STK CG31145, STK A2, STK PAKm, and STK MKNK1II were upregulated by exposure to amitraz, which indicates that they are potentially involved in conferring tolerance to amitraz.…”

Tyramine receptor drives olfactory response to (E)-2-decenal in the stink bugHalyomorpha halys

“…Many studies support the physiological role of TAR1 in processes such as locomotion (Saraswati et al, 2004;Schützler et al, 2019), metabolic control (Nishimura et al, 2005;Li et al, 2017;Roeder, 2020), reproduction (Hana & Lange, 2017a;Hana & Lange, 2017b) and olfaction (Kutsukake et al, 2000;Brigaud et al, 2009;Duportets et al, 2010;McQuillan et al, 2012;Ma et al, 2015;Zhukovskaya & Polyanovsky, 2017;Ma et al, 2019b). The TAR1 expression patterns mirror its functional roles because the TAR1 gene is highly expressed in the CNS, salivary glands and antennae in different insect species (Duportets et al, 2010;McQuillan et al, 2012;Wu et al, 2014;El-Kholy et al, 2015;Hana & Lange, 2017a;Ma et al, 2019a;Finetti et al, 2020). Two studies conducted in 2017 on the honeybee brain showed that TAR1 was mainly expressed at the presynaptic sites in antennal lobe OSNs and in the mushroom bodies PNs, which are essential structures for the olfactory system in insects (Synakevitch et al, 2017;Thamm et al, 2017).…”

“…xylostella (Ma et al, 2019a) suggesting that TAR1 could be involved in male specific functions such as development as well as reproduction. The high brain expression of HhTAR1 correlates well with the abundance of TAR1 in CNS of numerous insect species (El-Kholy et al, 2015;Hana & Lange, 2017a;Finetti et al, 2020) where it regulates several sensory processes (Roeder et al, 2003;Lange, 2009;Ohta & Ozoe, 2014;Neckameyer & Leal, 2017).…”