5-hydroxytryptamine in the salivary glands of adult female Aedes aegypti and its role in regulation of salivation.
A dense plexus of axons, immunoreactive to antisera against 5-hydroxytryptamine (5-HT, serotonin) and surrounding the proximal medial lobe of the salivary gland of adult female Aedes aegypti mosquitoes, was demonstrated by means of whole-mount fluorescence immunocytochemistry. This innervation originates in the stomatogastric nervous system. 5-HT-immunoreactive innervation is absent in male salivary glands, suggesting that 5-HT is involved in blood-feeding. Furthermore, female mosquitoes treated with the 5-HT-depleting agent alpha-methyltryptophan (AMTP) and then allowed to feed on a rat exhibited a significantly longer mean probing period and a lower blood-feeding success rate than did control mosquitoes. When female mosquitoes were experimentally induced to salivate into mineral oil, AMTP-treated individuals secreted significantly less saliva than did control mosquitoes. These samples of saliva also contained significantly lower concentrations of apyrase, an enzyme important in blood-feeding. Injection of 5-HT into both AMTP-treated and control mosquitoes elicited significant increases in the volume of secreted saliva and/or its apyrase content. We conclude that 5-HT plays an important role in the control of salivation in adult female A. aegypti.
Novak
M G
MG
Arizona Research Laboratories, University of Arizona, Tucson 85721.
Ribeiro
J M
JM
Hildebrand
J G
JG
D000330:Aedes / Q000502:physiology*; D000818:Animals; D005260:Female; D005455:Fluorescent Antibody Technique; D012469:Salivary Glands / Q000737:chemistry / Q000294:innervation; D012472:Salivation / Q000187:drug effects / Q000502:physiology*; D012701:Serotonin / Q000032:analysis* / Q000502:physiology*; D014364:Tryptophan / Q000031:analogs & derivatives / Q000494:pharmacology
C020774:alpha-methyltryptophan; D012701:Serotonin; D014364:Tryptophan