Further studies on anti-inflammatory activity of maprotiline in carrageenan-induced paw edema in rat.

Antidepressant drugs are commonly used for treatment of different medical disorders besides of psychiatric diseases. Accumulating evidence suggests that antidepressants exhibit anti-inflammatory activity in vivo and in vitro conditions, but the mechanisms of this property are not clear very well. In our earlier work, we demonstrated that i.c.v. and i.p. injection of maprotiline, as an antidepressant, decreased paw edema at the fourth hour after subplantar injection of carrageenan. Therefore, this work was undertaken to investigate anti-inflammatory effects of maprotiline in more details. Our results verified that i.p. (25 and 50 mg/kg) and i.c.v. (100 µg/rat) application of maprotiline significantly reduced paw edema at 1, 2, 3 and 4 h intervals after carrageenan challenge. Pathological examinations and MPO activity also showed that both i.p. and i.c.v. maprotiline considerably inhibited infiltration of PMN leucocytes into the inflamed paws. Additionally, i.p. and i.c.v. maprotiline at all applied doses noticeably declined levels of IL-1ß into the site of inflammation, while only i.p. maprotiline at a dose of 50 mg/kg significantly decreased TNF-α levels in the carrageenan-injected paws. These results confirmed anti-edematogenic activity of i.p. and i.c.v. maprotiline in the carrageenan induced paw edema model and showed that these properties of maprotiline might be mediated through inhibition of PMN infiltration and release of IL-1ß and TNF-α.

A study on the mechanisms involving the anti-inflammatory effect of amitriptyline in carrageenan-induced paw edema in rats.

Anti-inflammatory effects of antidepressants have been reported in some studies, but the mechanisms underlying these effects remain unknown. Amitriptyline, a tricyclic antidepressant, is widely used in the management of psychological disorders and various types of pain, including neuropathic pain or fibromyalgia. In our previous work, we found the role of supraspinal mechanisms in the anti-inflammatory effect of amitriptyline. In the line of the indicated study, we sought to evaluate the effects of intraperitoneal (i.p.) and intracerebroventricular (i.c.v.) application of amitriptyline in the carrageenan-induced paw edema in rats in more details. Our findings confirmed that i.p. (40 and 80 mg/kg) and i.c.v. (100 µg/rat) injection of amitriptyline inhibited carrageenan-induced inflammation at different times. We also found that both i.p. and i.c.v. amitriptyline significantly decreased migration of polymorphonuclear (PMN) leucocytes into the site of inflammation, according to pathological evidence and the activity of myeloperoxidase (MPO). Furthermore, i.p. amitriptyline at the applied doses markedly reduced interleukin (IL)-1ß and tumor necrosis factor (TNF)-α levels in the paw treated with carrageenan. Our results also showed that i.c.v. amitriptyline noticeably decreased the concentration of IL-1ß in the inflamed paws. The TNF-α levels reduced in the i.c.v. group, even though these reductions were not statistically significant. These results confirmed the anti-inflammatory effects of systemic and central amitriptyline in the carrageenan-induced paw edema in rats, and demonstrated that these effects mediated mostly through the inhibition of PMN cells migration and release of IL-1ß and TNF-α into the site of inflammation.