-

Objective: To investigate the role of central histamine Hi
and H2 receptors on food intake in freely feeding and food
- deprived rabbits.
Design: Experimental study.
Animals: Forty - two male New Zealand white rabbits
weighing between 2.5 - 3 Kg.
Procedure: A 23- gauge, 18mm long stainless steel guide
cannula was surgically implanted into the lateral ventricle
of brain, Intracerebroventricular injections of normal saline (control), promethazine and ranitidine at the same
doses of 50, 100 and 200 jig /rabbit in a volume of 25 ul
were performed using a 25 jil Hamilton’s syringe.
Cumulative food intake was measured in freely feeding
and food - deprived rabbits at the 0.5, 1, 2, 3, 6 and 24h
after injections.
Statistical analysis: Paired t-test, Factorial ANOVA and
Duncan’s test.
Results: Food deprivation for i6hincreased0.5, 1,2,3 and 6h cumulative food intake. In freely feeding rabbits,
promethazine (50 jig) had no effect on food intake, and at
the dose of 100 pg increased 1 and 2h feeding after
injection, but at the dose of 200 pg increased 2 and 3h post-
injection food intake. In the 1 6h food- deprived rabbits
promethazine (50,100 and 200 jig) had no effect.
Ranitidine at the doses of 50,100 and 200 pg produced no
significant changes on food intake in both freely feeding
and food- deprived rabbits. Prometliazine did not exert any
significant effects on the 6 and 24h post- injection food
intake.
Conclusion: Based on the results of the present study it is
concluded that the blockade of central Hi but not H2
receptors induce a short- lasting e citatory effect on food
intake. Thus, central Hi receptor may have an important role in the central control of feeding behavior.
J.Fac. Vet. Med. Univ. Tehran. 60,3:277-282,2005