OBJECTIVE: The parasympathetic transmitters vasoactive intestinal peptide (VIP) and substance P are secretagogues in salivary glands of animals. Currently, we hypothesise that in human salivary glands, these neuropeptides and the VIP-related peptide histidine methionine (PHM) also exert secretory actions, reflected morphologically by exocytosis of acinar protein/glycoprotein-storing granules. MATERIALS AND METHODS: Submandibular and parotid gland tissues, exposed in vitro to VIP and PHM, and substance P, respectively, were examined by light and transmission electron microscopy. For comparison, the response to in vitro stimulation of isoproterenol, phenylephrine and carbachol was examined. Moreover, the peptidergic innervation of the glands was examined by immunohistochemistry. RESULTS: VIP- and PHM-immunoreactive nerves were in close proximity to acini and ducts in the two glands, while these elements lacked a substance P-positive innervation. While no morphological changes occurred in response to substance P (parotid glands), VIP and PHM administration (submandibular glands) caused conspicuous acinar degranulation accompanied by luminal space broadening. In the two glands, both α1 - and β-adrenergic receptor stimulation and muscarinic receptor stimulation caused similar changes as to VIP/PHM, although to varying extent. CONCLUSIONS: VIP and PHM, but not substance P, are likely transmitters in the parasympathetic control of salivary (protein) secretion in humans. This article is protected by copyright. All rights reserved.
Effect of the neuropeptides vasoactive intestinal peptide, peptide histidine methionine and substance P on human major salivary gland secretion
QUARTU, MARINA;BOI, MARIANNA;ISOLA, MICHELA;LOY, FRANCESCO;SERRA, MARIA PINA
2014-01-01
Abstract
OBJECTIVE: The parasympathetic transmitters vasoactive intestinal peptide (VIP) and substance P are secretagogues in salivary glands of animals. Currently, we hypothesise that in human salivary glands, these neuropeptides and the VIP-related peptide histidine methionine (PHM) also exert secretory actions, reflected morphologically by exocytosis of acinar protein/glycoprotein-storing granules. MATERIALS AND METHODS: Submandibular and parotid gland tissues, exposed in vitro to VIP and PHM, and substance P, respectively, were examined by light and transmission electron microscopy. For comparison, the response to in vitro stimulation of isoproterenol, phenylephrine and carbachol was examined. Moreover, the peptidergic innervation of the glands was examined by immunohistochemistry. RESULTS: VIP- and PHM-immunoreactive nerves were in close proximity to acini and ducts in the two glands, while these elements lacked a substance P-positive innervation. While no morphological changes occurred in response to substance P (parotid glands), VIP and PHM administration (submandibular glands) caused conspicuous acinar degranulation accompanied by luminal space broadening. In the two glands, both α1 - and β-adrenergic receptor stimulation and muscarinic receptor stimulation caused similar changes as to VIP/PHM, although to varying extent. CONCLUSIONS: VIP and PHM, but not substance P, are likely transmitters in the parasympathetic control of salivary (protein) secretion in humans. This article is protected by copyright. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.