Adrenergic responses in human small arteries isolated from the femoral neck

Abstract

Many pathological bone conditions are accompanied by changes in bone perfusion. However, no method has yet allowed investigation of vascular reactivity in human bone tissue. In the present study, arterial segments (diameter = 0.25 mm) were isolated from human bone biopsies and mounted as ring preparations in vitro. The viability of the arteries and the effects of adrenoceptor stimulations were investigated. Combined a-and 0-adrenoceptor stimulation (noradrenaline 10-8-10-5 M) and specific cyIadrenoceptor stimulation (phenylephrine, 10-8-10-4.5 M ) induced ' concentration-dependent contractions in all arteries. Selective stimulation of a2-receptors (B-HT 933, 1 O-R-10-'.5 M) only induced contraction in three of eight arteries. Stimulation of 0-receptors with isoprenaline ( M ) resulted in vasorelaxation in 3 of 10 arteries. In all arteries, acetylcholine ( 10-'0-10-5 M ) induced vasorelaxation, demonstrating preserved function of the endothelium. The results suggest that primarily a1 -receptors are responsible for adrenoceptor induced vasoconstriction in human bone while functional a?-and 0-receptors may not be consistently expressed. The model is the first to allow investigations on vascular reactivity in human bone tissue and may become valuable for assessment of both normal and pathological bone physiology.

Reactivity of intraosseous femoral head arteries after long term glucocorticoid treatment: An experimental study in immature pigs

“…For the first time, intraosseous femoral head arteries were mounted on a myograph for in vitro testing of responses to vasoactive substances in this study. Vasoconstriction elicited by noradrenaline in the untreated animals was not altered by long term treatment with methylprednisolone and was comparable to data obtained in resistance arteries from the distal femur in pigs [14] and the femoral neck in humans [13]. The sensitivity m noradrenaline was enhanced by steroid treatment in the rat hindlimb [18].…”

Development of Rat Tibia Innervation: Colocalization of Autonomic Nerve Fiber Markers with Growth-Associated Protein 43

“…The sympathetic nervous system controls bone resorption by influencing osteoclasts and osteoblasts as well as regulating osseal blood flow [Trotman and Kelly, 1963;Takeda et al, 2002]. Vasoactive intestinal polypeptide (VIP) is known as a potent vasodilator, while noradrenaline causes a vasoconstrictory effect on resistance vessels isolated from the cancellous bone [Lundgaard et al, 1997[Lundgaard et al, , 2001. Unloading-induced bone loss occurs through the control mediated via the sympathetic nervous system [Kondo et al, 2005].…”