Effects of octopamine on fluid secretion by isolated salivary glands of a feeding ixodid tick
✍ Scribed by Tom Pannabecker; Dr. Glen R. Needham
- Publisher
- John Wiley and Sons
- Year
- 1985
- Tongue
- English
- Weight
- 596 KB
- Volume
- 2
- Category
- Article
- ISSN
- 0739-4462
No coin nor oath required. For personal study only.
✦ Synopsis
Octopamine elicited a dose-related secretory response by salivary glands isolated from the feeding female tick Amblyomrna americanum. Half-maximal stimulation occurred at about 60 pM. Phentolarnine (10 p M ) failed to inhibit the octoparnine-mediated response; however, thioridazine (50 pM) inhibited both octopamine (1,000 pM) and dopamine-stimulated (0.1 pM) secretion.
Maximal stimulation by dopamine (1.0 pM) showed no further increase in the rate of secretion after adding octopamine (1,000 or 0.1 PM). Glands responded to octoS:.rnine (100 pM) with rates significantly lower than controls following exposure to amphetamine (1,000 pM). Octopamine receptors do not appear to mediate the secretory response, and octopamine may stimulate secretion by releasing catecholamines from presynaptic neurons. These results support the hypothesis that dopamine is the natural transmitter mediating fluid secretion in the feeding tick salivary gland.