Effect of Long-Term Centrally Injected Histamine and Its Receptors Antagonist on The Hypothalamic Cyclooxygenase and Lipoxygenase Enzymes in Rats

The current study was designed to determine the effect of centrally chronic-administrated histamine and histaminergic receptors antagonist on the hypothalamic cyclooxygenase (COX) and lipoxygenase (LOX) enzymes amount. Studies were performed in male Sprague–Dawley rats. Histamine (100 nmol), histaminergic H1 receptor antagonist chlorpheniramine (100 nmol), histaminergic H2 receptor antagonist ranitidine (100 nmol) or histaminergic H3/H4 receptor antagonist thioperamide (100 nmol) was injected intracerebroventricularly for 7 days. Central chronic histamine treatment caused an increase in all three enzymes amount in the hypothalamus. Histaminergic receptors antagonist chronic-treatments with chlorpheniramine, ranitidine and thioperamide produced to decrease in hypothalamic COX-1 amount and to increase in hypothalamic COX-2 and LOX amounts. In conclusion, our findings show that the central histaminergic system has a potential for effect the central COX and LOX pathways. This could be interpreted that central histaminergic and central COX and LOX pathways have an interaction to regulate in many central nervous system functions.