| Popis: |
Studies on insects and crustacea have established octopamine as an important chemical messenger with multifunctional roles in arthropods (Evans, 1985). However there is relatively little information describing the octopaminergic system of ticks, an economically and medically important group of ectoparasites. The acaricidal properties of the formamidines, a class of chemical believed to act as octopaminergic agonists (Hollingworth, 1976), suggest that octopamine is an important neurotransmitter/neurohormone in ticks and the demonstration of an octopamine-sensitive adenylate cyclase in the CNS of Boophilus microplus (Morton, 1984) is consistent with such a role. The aim of our work is the characterisation of the enzymes involved in the synthesis and metabolism of octopamine in the cattle tick, B. microplus. In this report properties of tyramine-β-hydroxylase (T-β-H) from the synganglion of B. microplus are described and compared to the well-characterised mammalian enzyme, dopamine -β-hydroxylase (D-β-H). |
