From syn- + ganglion
synganglion (plural synganglia)
- (acarology) A nerve mass located near the esophagus in certain ticks.
2015 July 10, “SNP Analysis Infers that Recombination Is Involved in the Evolution of Amitraz Resistance in Rhipicephalus microplus”, in PLOS ONE, DOI:10.1371/journal.pone.0131341:
It is thought that amitraz is a potential agonist of the octopaminergic system located in the tick synganglion.