Effects of different levels of dietary Citrus Limon essential oil on some blood parameters and antioxidant status in Afshari Ewes.

Citrus Limon Oil (CLO) is known as antioxidant resource and contains limonoids, flavonoids and phenolic compounds. This study was conducted to investigate the effects of different levels of CLO on blood parameters and antioxidant status in Afshari ewes. Six adults Afshari ewes (3-4 years old and 51±5 kg) were randomly allocated to 3×3 Latin square design with three diets in 21 days period. Dietary treatments included:1) control diet, 2) control diet with 200 mg/day CLO, and 3) control diet with 400 mg/day CLO. To evaluate the antioxidant effect of the CLO, sustainable elimination of free radicals by DPPH and ABTS methods were used. The antioxidant activity of essential oils in DPPH method at doses of 32.5, 45, 130, 260 and 520 mg/ml were 9, 16, 31, 49 and 89%, respectively. Also, antioxidant activity of essential oils in ABTS method at doses of 32.5, 45, 130, 260 and 520 mg/ml were 49, 73, 81, 89 and 95%, respectively. CLO treatments did not affect glucose, blood urea nitrogen, albumin, total protein, low density lipoprotein, while improved the concentration of high-density lipoprotein (P>0.01). Results showed that supplementation with CLO significantly decreased (P<0.01) cholesterol, triglycerides and very low density lipoprotein concentrations compared with control. There was no significant difference in analyzed blood bio-chemicals and serum enzymes level between different antioxidant activity methods and groups, suggesting general well-being of ewes. These results suggest that, CLO supplementation had a positive impact on blood traits and antioxidant status of the Afshari ewes.

The effect of intracerebroventricular injection of histamine in visceral nociception induced by acetic acid in rats.

OBJECTIVE: This study was designed to investigate the role of brain histamine and H1 and H2 receptors in mediating the central perception of visceral pain in rats. MATERIALS AND METHODS: In conscious rats implanted with a lateral brain ventricle cannula, the effect of intracerebroventricular (i.c.v.) injection of histamine (2.5, 10, and 40 µg), and chlorpheniramine and ranitidine at the same doses of 5, 20, and 80 µg were investigated on visceral pain. Visceral nociception induced by intraperitoneal (i.p.) injection of acetic acid (1 mL, 1%), and the number of complete abdominal wall muscle contractions accompanied with stretching of hind limbs (writhes) were counted for 1 h. RESULTS: Histamine at doses of 10 and 40 µg and chlorpheniramine and ranitidine at the same doses of 20 and 80 µg, significantly decreased the numbers of writhes (P < 0.05). Pretreatment with chlorpheniramine and ranitidine at the same dose of 80 µg, significantly prevented histamine (40 µg)-induced antinociception (P < 0.05). CONCLUSION: The results of this study suggest that brain histamine may be involved in modulation of visceral antinociception through both central H(1)and H(2)receptors.

Role of central muscarinic cholinergic receptors in the formalin-induced pain in rats.

OBJECTIVES: In the present study, central effects of physostigmine and atropine have investigated in the formalin-induced pain in rats. MATERIALS AND METHODS: In conscious rats implanted with an intracerebroventricular (i.c.v.) cannula, the effects of i.c.v. injection of physostigmine and atropine were investigated on the formalin test in the rat. Formalin test was induced by subcutaneous (s.c.) injection of formalin (50 mul, 1%) in ventral surface of left hind paw, and durations of licking and biting of the injected paw were measured in 5-min blocks for 1 h. RESULTS: FORMALIN PRODUCED A BIPHASIC RESPONSE (FIRST PHASE: 0-5 and second phase: 15-40 min) in durations of licking and biting of the injected paw. Physostigmine at doses of 2.5, 5 and 10 ug significantly (P < 0.05) attenuated both first and second phases of pain response. Atropine (5 and 10 ug), used alone, produced no significant effect on pain, but pretreatment with atropine (10 ug) significantly (P < 0.05) blocked antinociception induced by physostigmine (5 ug). CONCLUSION: These results indicate that i.c.v. physostigmine can affect both neurogenic and inflammatory phases of formalin-induced pain through a mechanism in which the muscarinic cholinergic receptors are involved.

Antinociception induced by central administration of histamine in the formalin test in rats.

In the present study, effects of intracerebroventricular (icv) administration of histamine, mepyramine (H1-receptor antagonist) and famotidine (H2-receptor antagonist) have been investigated on the formalin test in rats. Subcutaneous injection of formalin (50 microl, 1%) into the ventral surface of the left hind paw produced a marked biphasic pain response (first phase: 0-5 min and second phase: 15-45 min). All the performed treatments did not significantly influence the first phase of pain. Histamine at the doses of 10 and 40 microg and mepyramine and famotidine at the same doses of 20 and 80 microg, significantly (P < 0.05) decreased the late phase of formalin-induced pain. Pretreatments with mepyramine and famotidine at the same dose of 80 microg, significantly (P < 0.05) prevented the histamine (40 microg)-induced antinociception. These results indicate that brain histamine produces antinociception, and both central H1 and H2 receptors may involve in the histamine-induced antinociception in the formalin test in rats.