Journal of Neuroscience Methods 79 (1998) 75 – 78 Axonal transport of herpes simplex virus-1 in an in vitro model based on the isolated sciatic nerve of the frog Rana ridibunda E. Maratou b , G. Theophilidis a, *, M. Arsenakis b a Laboratory of Animal Physiology, School of Biology, Aristotle Uniersity of Thessaloniki, Thessaloniki 54006, Macedonia, Greece b Laboratory of General Microbiology, School of Biology, Aristotle Uniersity of Thessaloniki, Thessaloniki 54006, Macedonia, Greece Received 23 May 1997; received in revised form 8 August 1997; accepted 30 September 1997 Abstract An in vitro model for the study of the axonal transport of herpes simplex virus-1 (HSV-1) in the nerve fibres of the sciatic nerve of the frog Rana ridibunda, has been developed. The nerve was placed along a three-chambered bath consisting of three isolated chambers arranged in series: the stimulating, perfusion and recording chambers. The HSV-1 inoculum was placed in the stimulating chamber, where the proximal part of the isolated sciatic nerve was immersed. HSV-1 was detected after 24 – 36 h in the recording chamber, where the distal part of the nerve was immersed in Dulbecco’s Modified Eagle Medium (DMEM), indicating an axonal transport speed of 46–60 mm/day. The evoked maximum compound action potentials generated in the stimulating chamber was monitored continuously in the recording chamber as an indication of the viability of the nerve during axonal transport. The in vitro method presented here is a useful tool for the pharmacological study of various parameters, e.g. drugs diluted in the perfusion chamber, ionising radiation and temperature, which may affect the axonal transport or other properties of HSV-1. © 1998 Elsevier Science B.V. Keywords: Axonal transport; In vitro; Herpes simplex virus-1; Frog; Sciatic nerve 1. Introduction Among neurotropic viruses herpes simplex viruses (HSV) interact in a unique, sophisticated manner with the human nervous system. Axonal transport mecha- nisms of HSV-1 (for example: transport speed, depen- dence on active transport mechanisms and impairment by colchichine etc) have already been established using in vitro and in vivo systems. For in vivo studies animal model systems (only mammals) have been extremely useful (for review see Kuypers and Ugolini, 1990; Gier- oba et al., 1991). The success of these models has led to the use of HSV as a transneuronal marker for the tracing of neuronal connections and for the identifica- tion of neural pathways derived from either cranial or spinal nerves (Ugolini, 1992). For in vitro studies cell culture model systems have been used (Bergstrom and Lycke, 1990; Penfold et al., 1994). This paper describes a novel in vitro model, the isolated sciatic nerve of the frog Rana ridibunda, which can be applied in pharmacological studies concerning HSV-1. 2. Materials and methods In this study, sciatic nerves of the frog Rana ridi - bunda, of either sex, were used. The animals, weighing between 140–180 g, were stunned, decapitated and pithed. The sciatic nerves were dissected from each leg, from the spinal cord to the knee, and placed in oxy- genated physiological solution (bubbled with 100% O 2 ) consisting of 111 mM NaCl, 2.41 mM KCl, 10 mM * Corresponding author. Tel.: +30 31 996861/998288; fax: +30 31 998269; e-mail: theophil@bio.auth.gr 0165-0270/98/$19.00 © 1998 Elsevier Science B.V. All rights reserved. PII S0165-0270(97)00166-0