Cholecystokinin- and gastrin-induced protein and amylase secretion from the parotid gland of the anaesthetized rat.
I.V. infusion of pentagastrin (20 microg/kg/h) or cholecystokinin (CCK)-8 (1 microg/kg/h) for 10 min caused secretion of salivary proteins from the parotid gland in the anaesthetized rat without any accompanying overt fluid secretion. This "occult" response was revealed by a subsequent wash-out injection of methacholine (5 microg/kg, I.V.) 10 min after the end of the infusion period (aiming at avoiding synergistic interactions). While the fluid response to methacholine was unaffected by the preceding infusion of pentagastrin and CCK-8, the output of protein increased by 147% (pentagastrin) and 74% (CCK-8) and that of amylase by 45% (CCK-8) compared to the responses to methacholine upon saline infusion. Those increases were abolished by the CCK-A receptor blocker (lorglumide), but not by the CCK-B receptor blocker (itriglumide). Evisceration, combined sympathetic and parasympathetic denervation of the glands and assay under adrenoceptor blockade excluded contribution from the gastro-intestinal tract, central or ganglionic mechanisms and circulating catecholamines to the increase in protein/amylase. Furthermore, Western blot demonstrated CCK receptors for both A and B subtypes in normal and chronically denervated glands. In the submandibular gland, both pentagastrin and CCK-8 evoked a trace secretion of saliva but, under the present experimental set-up, no statistically significant increase in protein output. Thus, in addition to the autonomic nervous system, gastrointestinal hormones may, in some types of glands, be involved in the secretion of salivary gland proteins.
Aras
Hülya Cevik
HC
Department of Pharmacology, Institute of Physiology and Pharmacology, The Sahlgrenska Academy at Göteborg University, Medicinaregatan 15 D, 413 90 Göteborg, Sweden.
Ekström
J
J
D000681:Amylases / Q000378:metabolism*; D000758:Anesthesia; D000818:Animals; D005260:Female; D041981:Gastrointestinal Tract / Q000502:physiology; D016210:Methacholine Chloride / Q000494:pharmacology; D017764:Parasympathectomy; D010306:Parotid Gland / Q000187:drug effects* / Q000294:innervation / Q000378:metabolism*; D010418:Pentagastrin / Q000494:pharmacology*; D010424:Pentobarbital; D051381:Rats; D017207:Rats, Sprague-Dawley; D043886:Receptor, Cholecystokinin A / Q000096:biosynthesis; D043887:Receptor, Cholecystokinin B / Q000096:biosynthesis; D012471:Salivary Proteins and Peptides / Q000378:metabolism*; D012472:Salivation / Q000187:drug effects; D012844:Sincalide / Q000494:pharmacology*; D013363:Submandibular Gland / Q000187:drug effects / Q000378:metabolism; D013562:Sympathectomy
D043886:Receptor, Cholecystokinin A; D043887:Receptor, Cholecystokinin B; D012471:Salivary Proteins and Peptides; D016210:Methacholine Chloride; D000681:Amylases; D010418:Pentagastrin; D010424:Pentobarbital; D012844:Sincalide