in view of recent demonstration that peptide hormones can penetrate the intracellular space in some tissues and the reports that intracellular injections of the neurotransmitter , dopamine , into acinar cells of cockroach salivary gland cause stimulation it seems of fundamental importance to test directly whether introduction of peptide secretagogues inside acinar cells of mammalian exocrine tissue can induce cell activation without first interacting with the outer surface of the external cell membrane .
C0007634
cells
C0699040
surface of