[Anacollagenase by the action of amitriptyline on Clostridium histolyticum collagenase]

Intraperitoneal injection of a mixture of collagenase (300 U) and amitriptyline (Laroxyl*, 3 mg) induce no lesions in contrast with the severe effects of collagenase alone. Also, a complete resistance to intraperitoneal collagenase injection is observed when preceded by 3 intramuscular injections of the same mixture (associated with Freund's incomplete adjuvant). This is due to the development of collagenase antibodies, as demonstrated by nephelometry and immunodiffusion. These facts show that amitriptyline neutralizes the enzymatic properties of collagenase, without alterring its antigenicity. We propose to call this new substance anacollagenase. Such a phenomenon has never been observed with a drug. However we got identical results with other tricyclic depressants (clomipramine, imipramine, doxepine, iprindole). The mechanism of the transformation of collagenase into anacollagenase is not yet explained.