Guanine nucleotides regulate the effect of substance P on striatal adenylate cyclase of the rat

Biochem Biophys Res Commun. 1990 Feb 28;167(1):211-5. doi: 10.1016/0006-291x(90)91752-e.

Abstract

Substance P was incubated in an adenylate cyclase assay of a particulate fraction of caudate-putamen tissue of the rat in order to examine the effect of the peptide on D-1 receptor coupled adenylate cyclase in vitro. Substance P did not influence basal adenylate cyclase activity or the stimulation of the enzyme by dopamine. No influence of substance P was seen on the effects of calcium and magnesium chloride as a cofactor of adenylate cyclase. Also the inhibition of adenylate cyclase activity by the dopamine antagonist fluphenazine was not influenced by substance P. However, substance P was able to enhance cyclic AMP formation in the presence of guanosine-imidodiphosphate (Gpp(NH)p), whereas the stimulatory effect of guanosine-triphosphate (GTP) was inhibited by substance P. In our study we suggest that substance P interacts with the guanine nucleotide regulatory subunit without directly affecting D-1 dopamine receptors in the caudate-putamen of the rat.

MeSH terms

  • Adenylyl Cyclases / metabolism*
  • Animals
  • Calcium / pharmacology
  • Caudate Nucleus / drug effects
  • Caudate Nucleus / enzymology
  • Corpus Striatum / drug effects
  • Corpus Striatum / enzymology*
  • Dopamine / pharmacology
  • Female
  • Fluphenazine / pharmacology
  • Guanine Nucleotides / physiology*
  • Guanosine Triphosphate / pharmacology
  • In Vitro Techniques
  • Magnesium Chloride / pharmacology
  • Rats
  • Rats, Inbred Strains
  • Substance P / pharmacology*

Substances

  • Guanine Nucleotides
  • Magnesium Chloride
  • Substance P
  • Guanosine Triphosphate
  • Adenylyl Cyclases
  • Fluphenazine
  • Calcium
  • Dopamine