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This Article Full Text Full Text (PDF) All Versions of this Article: 91/3/561    most recent expphysiol.2006.033217v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Lesclous, Ph. Articles by Saffar, J. L. Search for Related Content PubMed PubMed Citation Articles by Lesclous, Ph. Articles by Saffar, J. L. Related Collections Renal

¹ Laboratoire sur la réparation et les remodelages oro-faciaux, EA 2496, Université Paris Descartes, Faculté de Chirurgie Dentaire, 92120 Montrouge, France

Short-term studies have shown that histamine is involved, via its H₂ receptors (H₂R), in the mediator network regulating trabecular bone loss in long bones of ovariectomized (OVX) rats. It is not known whether this effect of histamine persists over time or involves other skeletal sites. In this study, rats were maintained for 6 months postOVX and treated daily with saline or famotidine (10 mg kg^–1), an H₂R antagonist. At the end of the experimental period, femur trabecular bone mass was markedly decreased in OVX rats, whether or not they were treated with famotidine. In contrast, in the fourth lumbar vertebra, where bone loss starts later than in the femur, famotidine treatment attenuated the decline in trabecular bone volume, protected the trabecular architecture, maintained the thickness of the cortices and reduced the numbers of osteoclasts and tartrate-resistant acid phosphatase-positive preosteoclasts, whereas it had no influence on bone formation parameters. In vertebral bone marrow of OVX rats, the numbers of mast cells (MCs) and non-MC histamine-producing cells increased, while famotidine treatment significantly diminished both cell populations. These data show that H₂R antagonism does not protect trabecular bone mass in the long term, and that short-term protection involves all bones. Histamine is involved during the early phase of strong osteoclastic resorption but not during the late phase of slower resorption, suggesting that different mediator networks control the two phases of destruction. Histamine would be part of the network mediating the early phase.

(Received 9 January 2006; accepted after revision 13 February 2006; first published online 2 March 2006)
Corresponding author J. L. Saffar: Laboratoire sur la réparation et les remodelages oro-faciaux, Faculté de Chirurgie Dentaire, Université Paris Descartes, 1 rue Maurice Arnoux, 92120 Montrouge, France. Email: jean-louis.saffar{at}univ-paris5.fr