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  • Title: Effect of stress and cyclosporine on ornithine decarboxylase activity in rat submaxillary lymph nodes.
    Author: Esquifino AI, Arce A, Stern JE, Cardinali DP.
    Journal: Eur J Pharmacol; 1995 Oct 16; 285(2):143-9. PubMed ID: 8566132.
    Abstract:
    This study was performed: (1) to assess whether the stress produced in rats by daily turpentine oil injections for 5 days, or by restraining the animals for 30 min during 5 days, affected basal and Freund's adjuvant-stimulated submaxillary lymph node ornithine decarboxylase activity, an indicator of cell proliferation; (2) to analyze whether the activity of the immunosuppressive drug cyclosporine on submaxillary lymph node ornithine decarboxylase activation after Freund's adjuvant injection was modified in stressed rats; (3) to examine the mediation of stress effects on submaxillary lymph node ornithine decarboxylase activation by regional sympathetic or parasympathetic nerves. Animals subjected to a unilateral superior cervical ganglionectomy, or to a unilateral chorda tympani section, together with a contralateral sham-operation were employed. After turpentine oil or restraint stress, a significant decrease in submaxillary lymph node ornithine decarboxylase was found. A unilateral sympathetic denervation of submaxillary lymph nodes counteracted in part the inhibitory effect of stress on ornithine decarboxylase activation, as well as augmented the enzyme response in innervated submaxillary lymph nodes. Ornithine decarboxylase activation attained similar values in parasympathetic decentralized or intact submaxillary lymph nodes and the unilateral parasympathetic decentralization did not interfere with the inhibition of enzyme activity found in turpentine oil-stressed rats. Cyclosporine administration (5 or 20 mg/kg) significantly decreased Freund's adjuvant-induced ornithine decarboxylase activity in the submaxillary lymph nodes of control rats, but failed to modify it in turpentine oil-stressed animals. In this latter group, a higher (40 mg/kg) dose of cyclosporine decreased ornithine decarboxylase activity on the innervated side only. A diminished inhibitory response to cyclosporine was found in the parasympathetic decentralized submaxillary lymph nodes of unstressed rats. The results support the view that the immunosuppressive effects of cyclosporine may diminish during stress, in part due to changes in the traffic of neural signals in local sympathetic nerves.
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