[Comparative analysis of orexin-containing neurons reactions in the rat hypothalamus after lipopolysaccharide injection in different doses].

Nowadays many investigations are focused on the participation of orexin-containing neurons in CNS reactions caused by antigen injection, for instance lipopolysaccharide (LPS). The analysis of orexin-containing neuron: quantity in 2, 4 and 6 hours after injection of low non-septic dose of LPS in comparison with a higher subseptic dose, was carried on. The increase of the orexin-immunoractive neurons quantity was observed in 2 and 4 hours after administration of 25 meg/kg of LPS, whereas in 6 hours the decrease of it was demonstrated. Injection of higher dose of LPS (500 meg/kg) was shown to cause the more significant decrease of the quantity of orexin-positive neurons only in 6 hours after antigen administration. The obtained data evidence the alteration of orexin content detected in neurons somas and the shift of the balance of its synthesis and utilization processes in response to the LPS injection.