The wider significance of Ach is in understanding the biological effects of tested toxins and/or medical drugs: as any immunological effects of AChE inhibitors can involve both CNS and PNS, this has to be taken into consideration in interpreting any findings. For this reason, vagotomy, used to study the cholinergic anti-inflammatory pathway in animal experiments or selecting compounds that do not cross the blood brain barrier should be considered carefully before drawing any conclusions as to which pathway is involved in the proposed mechanism.