From the' School of Pharmacy, Mashhad University of Medical Sciences, Mashhad , lslamic Republic of Iran
Abstract: (4482 Views)
An alternative in vitro approach to drug screening has been the use of
human cell cultures for antiviral agents and microbial cell cultures for the
assessment of the carcinogenic potential of selected compounds. A number
of protozoan species have been also used as drug screens for anti-protozoal
agents. The ciliated protozoan Tetrahymena pyriformis species has been
widely utilised as a drug screen for a variety of pharmacologically active
agents.
Accordingly, it was decided to investigate whether T. pyriformis could
be used as a preliminary drug screen for evaluation of the local anaesthetic
activity and duration of action of certain commercially available local
anaesthetics. In this communication, the results of this new in vitro biological
drug screen are reported. It is based on the complete protozoan cell
immobilisation by the anaesthetic solution. A positive inverse correlation
was observed between the lowest concentration (minimum inhibitory
concentration=MIC) that wholly inhibits the mobility of all cells of T.
pyriformis and the duration of action of the test compounds. Generally, MIC
was high for the short-acting anaesthetics and low for the long-acting ones.
The results suggest the suitability of this new microbiological assay system for
the evaluation of local anaesthetic activity and duration of action and
possibly irritancy and toxicity of other local anaesthetics as well as potentially
active therapeutic agents which possess surface activity.