Trans-synaptic induction of adrenal tyrosine hydroxylase following amphetamine treatment in the rat

Thromboelastographic evaluation of the effectiveness of choline or CDP-choline treatment on endotoxin-induced hemostatic alterations in dogs

Sepsis/endotoxemia associates with coagulation abnormalities. We showed previously that exogenous choline treatment reversed the changes in platelet count and function as well as prevented disseminated intravascular coagulation (DIC) in endotoxemic dogs. The aim of this follow-up study was to evaluate the effect of treatment with choline or cytidine-5'-diphosphocholine (CDP-choline), a choline donor, on endotoxin-induced hemostatic alterations using thromboelastography (TEG). Dogs were randomized to six groups and received intravenously (iv) saline, choline (20 mg/kg) or CDP-choline (70 mg/kg) in the control groups, whereas endotoxin (0.1 mg/kg, iv) was used alone or in combination with choline or CDP-choline at the same doses in the treatment groups. TEG variables including R- and K-time (clot formation), maximum amplitude (MA) and α-angle (clot stability), G value (clot elasticity), and EPL, A, and LY30 (fibrinolysis), as well as overall assessment of coagulation (coagulation index - CI), were measured before and at 0.5-48 h after the treatments. TEG parameters did not change significantly in the control groups, except for CI parameter after choline administration. Endotoxemia resulted in increased R-time and A value (P < 0.05), decreased K-time (P < 0.05), α-angle (P < 0.001) and CI values (P < 0.01) at different time points. Treatment with either choline or CDP-choline attenuated or prevented completely the alterations in TEG parameters in endotoxemic dogs with CDP-choline being more effective. These results confirm and extend the effectiveness of choline or CDP-choline in endotoxemia by further demonstrating their efficacy in attenuating or preventing the altered viscoelastic properties of blood clot measured by TEG.

Participation of spinal monoaminergic and cholinergic systems in the regulation of adrenal tyrosine hydroxylase

The role of spinal pathways in the regulation of tyrosine hydroxylase activity (ATHA) in the adrenal medulla was characterized in adult rats with surgical transection of the upper thoracic cord. The animals received injections of centrally active agonists, which could then act on the sympathoadrenal preganglionic neurons isolated from their supraspinal afferents. All agonists tested produced distinct increases of tyrosine hydroxylase activity in rats with a surgical sham operation. The injection of quipazine or oxotremorine into spinalized rats led to decreased tyrosine hydroxylase activity. Clonidine and several dopamine agonists did not affect tyrosine hydroxylase activity. Considering the mechanism of the observed changes in tyrosine hydroxylase activity it is concluded that the changes are mediated by neural pathways and that variations in the secretion of adrenocorticotrophic hormone (ACTH) do not play a role. The results suggest (a) that there are serotonergic and cholinergic (muscarinic) receptors in the lower thoracic cord generating a net inhibitory action on tyrosine hydroxylase activity; and (b) that increases of tyrosine hydroxylase activity mediated by dopaminergic drugs probably originate from areas rostral to the thoracic cord. It is possible that an alpha-adrenergic system participates in the regulation of tyrosine hydroxylase activity in the adrenal medulla.