The (neuro)endocrine control of enzyme release from invertebrate digestive cells remains poorly understood. A tissue dissociation procedure was developed to investigate the regulatory mechanisms of α-amylase discharge from the cells of the stomach-digestive gland complex of the scallop Pecten maximus. The validity of the experimental system was tested by increasing the intracellular concentration of second messenger analogues (N6,2′-o-dibutyryl-adenosine-3′,5′ cyclic monophosphate and the ionophore A23187) known to mimic the activity of naturally occurring secretagogues in vertebrates: N6,2′-o-dibutyryl-adenosine-3′,5′ cyclic monophosphate increased the time and dose-dependent release of α-amylase in a similar way as in vertebrates. A23187 was also very effective in inducing enzyme discharge. Since the in vitro bioassay was shown to be functional and because axon terminals were previously seen in close contact to α-amylase secreting cells, the effect of some classic neurotransmitters was explored. Only the cholinergic agonist carbachol and dopamine evoked a secretory response. Maximal stimulation of α-amylase release was reached at 10-5 mol·l-1 carbachol; at the same concentration dopamine was less effective than carbachol. By contrast, serotonin was totally inactive. The in vitro bioassay should prove useful for the identification of regulatory molecules involved in the control of enzyme discharge and to study stimulus secretion coupling mechanisms in scallop digestive cells.