Effect of α-MSH upon cyclic AMP levels induced by the glutamatergic agonists NMDA, quisqualic acid, and kainic acid

• Published in: Peptides (New York, N.Y. : 1980) N.Y. : 1980), 1996, Vol.17 (8), p.1303-1306
• Main Authors: De Barioglio, Susana R., Brito, María Ines
• Format: Article
• Language: English
• Subjects: alpha-MSH - pharmacology; Animals; Caudate Nucleus - drug effects; Caudate Nucleus - metabolism; Caudate putamen; Cyclic AMP; Cyclic AMP - metabolism; Drug Interactions; Excitatory Amino Acid Agonists - pharmacology; In Vitro Techniques; Kainic acid; Kainic Acid - pharmacology; Male; MSH; N-Methylaspartate - pharmacology; NMDA; Nucleus Accumbens - drug effects; Nucleus Accumbens - metabolism; Putamen - drug effects; Putamen - metabolism; Quisqualic acid; Quisqualic Acid - pharmacology; Rats; Rats, Wistar
• ISSN: 0196-9781; 1873-5169
• DOI: 10.1016/S0196-9781(96)00229-X

This study was carried out to investigate possible interactions between some glutamatergic agonists and the peptide α-MSH upon the cyclic AMP levels. We used an in vitro tissue slice preparation incubated in the presence of different glutamatergic agonists such as N-methyl- d-aspartic acid (NMDA), quisqualic acid (QUIS), kainic acid (KA), and the peptide α-MSH together with each agonist. Slices containing caudate putamen and accumbens were chosen according to neurochemical data indicating that the striatum contains a moderate amount of MSH binding sites and also receives glutamatergic innervation. Exposure of these slices to either MSH or to the agonists NMDA or QUIS resulted in an increase in the cAMP levels in relation to controls. Nevertheless, incubation with KA resulted in no changes in the nucleotide levels. The combination of MSH/NMDA induced a reduction of cAMP levels in relation to those obtained with NMDA alone. The combinations of QUIS/MSH or KA/MSH also induced variations in the values of nucleotide in relation to the those obtained with the peptide alone or with the corresponding agonist; these changes were related to the dose of agonist used in each case. The results obtained in these experiments suggest the existence of some interaction between the peptide and the agonist used.