Histamine dependent cAMP generating system in rabbit CNS: interaction with various neuroregulators.

Histamine (HI) potently stimulated, through H2-receptors, cAMP accumulation in slices of the rabbit cerebral cortex (EC50: 15 microM; maximum stimulation: 300-450% of the basal level). Combination of L-noradrenaline or L-adrenaline and adenosine with HI showed synergistic and additive effects, respectively. Carbachol, arecoline and pilocarpine had no effect, while oxotremorine and tremorine increased and decreased the HI response when used at low or high concentrations, respectively.