Melatonin treatment decreases c-fos expression in a headache model induced by capsaicin.
The aim of the present work was to analyze c-fos response within the trigeminal nucleus caudalis (TNC) of pinealectomized rats and animals that received intraperitoneal melatonin, after intracisternal infusion of capsaicin, used to induce intracranial trigeminovascular stimulation. Experimental groups consisted of animals that received vehicle solution (saline-ethanol-Tween 80, 8:1:1, diluted 1:50) only (VEI, n=5); animals that received capsaicin solution (200 nM) only (CAP, n=6); animals submitted to pinealectomy (PX, n=5); sham-operated animals (SH, n=5); animals submitted to pinealectomy followed by capsaicin stimulation (200 nM) after 15 days (PX + CAP, n=7); and animals that received capsaicin solution (200 nM) and intraperitoneal melatonin (10 mg/kg) (CAP + MEL, n=5). Control rats, receiving vehicle in the cisterna magna, showed a small number of c-fos-positive cells in the TNC (layer I/II) as well as the sham-operated and pinealectomized rats, when compared to animals stimulated by capsaicin. On the other hand, pinealectomized rats, which received capsaicin, presented the highest number of c-fos-positive cells. Animals receiving capsaicin and melatonin treatment had similar expression of the vehicle group. Our data provide experimental evidence to support the role of melatonin and pineal gland in the pathophysiology of neurovascular headaches.
Tanuri
Fabiano C
FC
Departamento de Neurologia/Neurocirurgia, Universidade Federal de São Paulo, Escola Paulista de Medicina, São Paulo, Brazil. ftanuri@yahoo.com.br
de Lima
Eliângela
E
Peres
Mario F P
MF
Cabral
Francisco R
FR
da Graça Naffah-Mazzacoratti
Maria
M
Cavalheiro
Esper Abrão
EA
Cipolla-Neto
José
J
Zukerman
Eliova
E
Amado
Débora
D
D000704:Analysis of Variance; D000818:Animals; D002211:Capsaicin; D004195:Disease Models, Animal; D006261:Headache / Q000139:chemically induced / Q000188:drug therapy / Q000378:metabolism*; D007150:Immunohistochemistry; D007274:Injections, Intraperitoneal; D008297:Male; D008550:Melatonin / Q000008:administration & dosage / Q000502:physiology*; D008845:Microinjections; D010870:Pineal Gland / Q000601:surgery; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D014275:Trigeminal Caudal Nucleus / Q000187:drug effects / Q000378:metabolism*
D016760:Proto-Oncogene Proteins c-fos; D008550:Melatonin; D002211:Capsaicin