Heat shock protein expression in umbilical artery smooth muscle

Postpartum vasospasm in the umbilical arteries may be due to impaired vasor elaxation secondary to alterations in the expression of heat shock proteins . The contractile responses of pre- and full-term bovine umbilical artery s mooth muscles were determined in a muscle bath. Heat shock protein expressi on was determined in bovine and human arterial tissues using western blotti ng with specific antisera. Full-term bovine and human umbilical artery smoo th muscle was refractory to relaxation induced by the nitric oxide donor, s odium nitroprusside. This impaired vasorelaxation was associated with the e xpression of the inducible form of the heat shock protein, HSP70i, and incr eases in the expression of the small heat shock protein, HSP27. Small heat shock proteins have been implicated in modulating contraction and relaxatio n responses in vascular smooth muscles. Thus, alterations in heat shock pro tein expression may play a role in umbilical artery vasospasm.