Effects of prolonged reduction in blood flow on submandibular secretory function in anesthetized sheep.
Submandibular vascular and secretory responses to parasympathetic chorda-lingual (C-L) stimulation were investigated in anesthetized sheep before, during, and after an intracarotid (ic) infusion of endothelin-1 (ET-1). Stimulation of the peripheral end of the C-L nerve at 4 and 8 Hz produced a frequency-dependent reduction in submandibular vascular resistance (SVR) associated with a frequency-dependent increase in submandibular blood flow, salivary flow, and Na+, K+, and protein output from the gland. During stimulation at 4 Hz, ic ET-1 significantly increased SVR (P < 0.01), without significantly affecting either the aortic blood pressure or heart rate. Submandibular blood flow (SBF) was reduced by 48 +/- 4% and the flow of saliva by 50 +/- 1%. The effect on blood and salivary flow persisted for at least 30 min after the infusion of ET-1. The reduction in SBF was associated with a diminution in the output of Na+,K+, and protein in the saliva (P < 0.01). These effects persisted for 30 min after the infusion of ET-1 had been discontinued and were linearly related to the flow of plasma throughout.
Physiological Laboratory, University of Cambridge CB2 3EG, UK.
A S
AS
Thakor
C N
CN
Brown
A V
AV
Edwards
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002339:Carotid Arteries; D002814:Chorda Tympani Nerve / Q000502:physiology; D004558:Electric Stimulation; D004573:Electrolytes / Q000378:metabolism; D019332:Endothelin-1 / Q000008:administration & dosage; D005260:Female; D007269:Injections, Intra-Arterial; D008036:Lingual Nerve / Q000502:physiology; D011506:Proteins / Q000378:metabolism; D012039:Regional Blood Flow; D012756:Sheep; D013363:Submandibular Gland / Q000098:blood supply* / Q000187:drug effects / Q000378:metabolism*; D014655:Vascular Resistance / Q000187:drug effects
D004573:Electrolytes; D019332:Endothelin-1; D011506:Proteins