ABSTRACT
BACKGROUND: Systemic nitroglycerin (NTG) activates brain nuclei involved in nociceptive transmission as well as in neuroendocrine and autonomic functions in rats. These changes are considered relevant for migraine because NTG consistently provokes spontaneous-like migraine attacks in migraineurs. Several studies have suggested a relationship between the endocannabinoid levels and pain mediation in migraine. URB937, a peripheral inhibitor of fatty acid amide hydrolase (FAAH)-the enzyme that degrades anandamide, produces analgesia in animal models of pain, but there is no information on its effects in migraine. AIM: We evaluated whether URB937 alters nociceptive responses in the animal model of migraine based on NTG administration in male rats, using the tail flick test and the plantar and orofacial formalin tests, under baseline conditions and after NTG administration. Furthermore, we investigated whether URB937 affects NTG-induced c-Fos expression in the brain. RESULTS: During the tail flick test, URB937 showed an antinociceptive effect in baseline conditions and it blocked NTG-induced hyperalgesia. URB937 also proved effective in counteracting NTG-induced hyperalgesia during both the plantar and orofacial formalin tests. Mapping of brain nuclei activated by NTG indicates that URB937 significantly reduces c-Fos expression in the nucleus trigeminalis caudalis and the locus coeruleus. CONCLUSIONS: The data suggest that URB937 is capable of changing, probably via indirect mechanisms, the functional status of central structures that are important for pain transmission in an animal model of migraine.
Subject(s)
Amidohydrolases/antagonists & inhibitors , Cannabinoids/administration & dosage , Disease Models, Animal , Hyperalgesia/prevention & control , Hyperalgesia/physiopathology , Pain Perception/drug effects , Analgesics/administration & dosage , Animals , Dose-Response Relationship, Drug , Hyperalgesia/chemically induced , Male , Nitroglycerin , Rats , Rats, Sprague-Dawley , Treatment OutcomeABSTRACT
Creatine, an ergogenic compound essential for brain function, is very hydrophilic and needs a transporter to cross lipid-rich cells' plasma membranes. Hereditary creatine transporter deficiency is a severe incurable neurological disease where creatine is missing from the brain. Creatine esters are more lipophylic than creatine and may not need the transporter to cross plasma membranes. Thus, they may represent a useful therapy for hereditary creatine transporter deficiency. Creatine ethyl ester (CEE) is commercially available and widely used as a nutritional supplement. It was reported that it enters the cells of patients lacking the transporter but was not useful when administered in vivo, by oral route, to affected patients. In this paper we investigated the effects of CEE in in vitro brain slices before and after biochemical block of the creatine transporter. We found that CEE is rapidly degraded in the aqueous incubation medium to creatinine, however it remains in solution long enough to cause an increase in tissue content of creatine and, more prominently, phosphocreatine. Both CEE and creatine delayed the anoxia-induced failure of synaptic transmission, and there was no difference between the two compounds. Contrary to what we expected, CEE did not increase tissue creatine content after the creatine transporter was blocked. We confirm that CEE is probably not an effective treatment for hereditary creatine transporter deficiency. Two factors seem to affect the possibility for creatine esters to be exploited in the therapy of creatine transporter deficiency. First, the size of their alcohol moiety should be increased since this would increase the lipophilicity of the compound and improve its ability to diffuse through biological membranes. Second, creatine esters should be further modified to slow their degradation to creatinine and increase their half-life in aqueous solutions. Moreover, we should not forget the possibility that they are degraded in vivo by plasma esterases.
Subject(s)
Creatine/analogs & derivatives , Hippocampus/metabolism , Membrane Transport Proteins/deficiency , Animals , Chromatography, High Pressure Liquid , Creatine/metabolism , Male , Mice , Mice, Inbred ICR , Organ Culture Techniques , Spectrometry, Mass, Electrospray IonizationABSTRACT
A new method for isolation and characterization of peptides presented in the context of the nonclassical human leukocytes antigen (HLA) class I molecule HLA-E was developed. A combination of different chromatographic steps coupled with electrospray mass spectrometry allowed us to detect the presence of small amounts of a naturally processed human Cytomegalovirus (HCMV)-derived peptide isolated from the HEK-293T/HLA-E+/UL40+ transfected cells of from HELA cell line. The peptide sequence was confirmed by tandem mass spectrometry (MS/MS). This approach provides a versatile and sensitive method for direct identification of MHC class I-binding peptides that might be derive from different pathogen or tumor-associated proteins.
