Limited signal transduction repertoire of human Y(5) neuropeptide Y receptors expressed in HEC-1B cells

In HEC-1B cells transfected with human Y(5) neuropeptide Y (NPY) receptors (but not in non-transfected cells) NPY inhibited forskolin-stimulated cAMP accumulation in a pertussis toxin-sensitive manner (-log EC(50) 8.88 +/- 0.25). Elevations of intracellular CA(2+) were largely restricted to very high NPY concentrations and similar in transfected and nontransfected cells. NPY did not increase inositol phosphate accumulation and did not activate a variety of isoforms of protein kinase C or mitogen-activated protein kinases. We conclude that at least upon expression in HEC-1B cells the signal transduction of Y(5) NPY receptors is limited to inhibition of cAMP accumulation.