Transmembrane receptor cross-talk: concurrent VIP and alpha 1-adrenergic activation rapidly elevates pinealocyte cGMP...

The transmembrane regulation of cGMP accumulation, which is poorly understood, was studied using isolated rat pinealocytes. It was found for the first time that VIP stimulates cGMP accumulation several-fold. This stimulation was amplified by phenylephrine acting via alpha 1-adrenoceptors, resulting in a greater than 100-fold increase in cGMP accumulation. These results raise the possibility that cGMP accumulation in other tissues might be regulated by VIP, and that the stimulating effects of VIP might be markedly amplified by catecholamine transmitters in these tissues. It is also possible that other pairs of receptors might control large changes in cGMP in the central nervous system through parallel mechanisms.