Perturbation of tyraminergic/octopaminergic function inhibits oviposition in the cattle tick Rhipicephalus (Boophilus) microplus

• Published in: Journal of insect physiology Vol. 58; no. 5; pp. 628 - 633
• Main Authors: Cossío-Bayúgar, Raquel, Miranda-Miranda, Estefan, Narváez Padilla, Verónica, Olvera-Valencia, Francisco, Reynaud, Enrique
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.05.2012
• Subjects: Acaricides; Adrenergic Agents - pharmacology; Adrenergics; Amino Acid Sequence; Animals; beta-adrenergic agonists; Boophilus microplus; Cattle; Drosophila; epinephrine; Female; immunity; Molecular Sequence Data; norepinephrine; Octopamine; Octopamine - pharmacology; Oviposition; Oviposition - drug effects; receptors; Rhipicephalus; Rhipicephalus - drug effects; Rhipicephalus microplus; Tick; Tick Control; tick infestations; ticks; Tyramine; Tyramine; Acaricides; Octopamine; Adrenergics; Boophilus microplus; Tick; Oviposition; Rhipicephalus microplus
• ISSN: 0022-1910; 1879-1611
• DOI: 10.1016/j.jinsphys.2012.01.006

The cattle tick Rhipicephalus microplus, is one of the most damaging livestock ectoparasites. Tropical tick infestation limits the introduction of high-yield bovine varieties because they do not have immunity to the diseases transmitted by these ectoparasites. This tick is usually controlled with chemical acaricides but their indiscriminate use has created resistant populations. The discovery of new molecules that can be used for tick control is urgent. Based on the knowledge that octopamine, a biogenic amine analog to epinephrine, is central to the regulation of oviposition in several studied arthropods and that an imbalance in octopamine release causes sterility in a Drosophila model. Tyramine, octopamine and epinastine and 83 adrenergic compounds classified by their effect in the vertebrate systems were screened for their ability to block oviposition in Rhipicephalus microplus. Of these molecules, we found that 10 alpha-agonists, 3 alpha-antagonists, 5 beta-adrenergic agonists, 7 beta-antagonists and Norepinephrine were able to inhibit oviposition in this tick at pharmacological concentrations. Surprisingly, tyramine appears to be more potent than octopamine. The probable physiological causes of this inhibition are discussed. Our results suggest that although there are alpha adrenergic-like receptors in the tick, they do not behave in a manner completely analogous to their vertebrate counterparts.