Anxiety-like behavior induced by IL-1 beta is modulated by alpha-MSH through central melanocortin-4 receptor

CRAGNOLINI, ANDREA BEATRIZ; SCIMONELLI, TERESA NIEVES

Pinamar

Congreso; 20th Sociedad Argentina de Neuroquimica.; 2005

The proinflammatory cytokine IL-1b influences neuroendocrine activity and produces other effects, including fever and behavioral changes such as anxiety. The melanocortin neuropeptides, such as alpha-melanocyte stimulating hormone (MSH), antagonize many actions of IL-1, through specific melanocortin receptors (MCR) in the central nervous system. The objective of our study was to establish the effect the effect of MSH peptides on IL-1b-induced anxiety-like behavior and the melanocortin receptors involved. We evaluated the effects of intracerebroventricular administration of IL-1b induced an anxiogenic-like behavior and the melanocortin receptors involved. We evaluated the effects of intracerebroventricular administration of IL-1b (30ng) and MC-R agonists: a-MSH, an MC3/MC4-R agonist (0.2 ug) or g-MSH, an MC3 agonist (2ug) or HS014, an MC4-R antagonist (2ug), on an elevated plus-maze test. Injection of IL-1b induced an anxiogenic-like response, as indicated by reduced open arms entries and time spent on open arms. The administration of a-MSH reversed IL-1b-induced anxiety with co-administration of HS014 inhibiting the effect of a-MSH. However, the associated treatment with g-MSH did not affect the anxiety with co-administration of HS014 inhibiting the effect of a-MSH. However, the associated treatment with g-MSH, through central MC4-R can modulate the anxiety-like behavior induced by IL-1b. The finding that HS014 produced an increase in anxiety may indicate that endogenous a-MSH has an anxiolytic effect.