Developmental studies on vasoactive intestinal peptide, substance P and calcitonin gene-related peptide in salivary glands of postnatal rats.

The development of vasoactive intestinal peptide, substance P and calcitonin gene-related peptide in parotid, submandibular and sublingual glands of the male rat was followed by immunochemistry and immunocytochemistry. The total amounts of these peptides increased in surges during the first 8 weeks of the animal's life; one within 2-4 weeks and the other beginning 1-2 weeks later. Nerve fibres containing these peptides were present at birth showing a pattern of distribution similar to that in adults. During the first 4 weeks the nerve fibres increased in number.