Pentazocine-induced neuromuscular syndrome: clinical, histochemical features in two cases and a tissue culture study of pentazocine-block myogenesis in human foetal muscle.
Two cases of pentazocine-induced neuromuscular syndrome in addicted patients are reported. Histochemical and histographic analysis of muscle biopsies performed in areas distant from the site of injection, disclosed type II muscle fibre atrophy. In order to clarify the pentazocine myotoxic mechanism, a tissue culture study was performed and the effects of the drug on the extent of myogenesis in human foetal muscle cultures were assayed. The tissue culture studies showed: 1 a complete block of myogenesis in pentazocine-treated human foetal muscle cultures and 2. a delayed fusion process when the pentazocine-treated cultures were pretreated with 10(-5) M D-arabinofuranosylcytosine (ara-C). In conclusion it is suggested that the overgrowth of fibroblasts, supported by tissue culture study, in tissues other than muscle (i.e. nerve) could explain the neurogenic aspects found in these patients.