Methods of inducing analgesia or anesthesia and treating or preventing ischemic injury of tissues in general

DETAILED DESCRIPTION This invention is therefore aimed at solving the above-mentioned shortcoming of adenosinergic approaches, while obtaining either analgesic (anesthetic) or protective effects, thus providing similar or even greater beneficial effects than adenosinergic approaches without the troublesome hypotension.
Exogenous purinergic compounds delivered directly in the brain tissue via microdyalisis probes (thus avoiding hypotension that plagues systemic administration) (a well known technique for those skilled in the art of drug delivery for pharmacological studies and analysis of interstitial fluid levels of various substances including aminoacids) induces the release of a number of inhibitory aminoacids but especially taurine into the CNS interstitial space.
Therefore the logical conclusion is that some of the beneficial effects so far ascribed to adenosine could be actually due to this taurine, which is known to have important inhibitory, anticalcic and antioxidant activities, for which it has been described as the natural protective substance (Huxtable, 1980; Wright, 1986).
Ischemic injury involves Ca.
sup.
++ overload of cells and subsequent oxidation of lipid membrane and cytoskeleton structures; this phenomenon is particularly conspicuous in the excitable CNS tissue (Wieloch, 1982).
The anticalcic and antioxidant effects of taurine have been shown in the retina and various neural preparations (cultures, slices, synaptosomes) as well as in cardiac tissue, thus establishing the grounds for extending the protective effects to tissues other than the CNS as well, for the treatment or prevention of ischemic injury of a variety of organs.
For metabolic reasons (Lloyd, 1988; Schrader, 1991) the combined use of taurine with homotaurine or with methionine should result in mutually potentiating effects.
The simultaneous use of small amounts of purinergic compounds (not enough to produce significant hypotension) and taurine alone or taurine+homotaurine and/or with methionine are likewise supplementary and are expected to further potentiate mutually their analgesic and/or anesthetic, and protective effects