Synthetic egg-laying hormone of Aplysia: quantitative studies of induction of egg laying in Stylocheilus and of the activation of Aplysia buccal neuron B16.
1. Synthetic Aplysia egg-laying hormone (ELH-lysine-amide) elicited egg laying in Stylocheilus at a threshold dose of 0.5 microgram per recipient, estimated to be a concentration in the circulation of Stylocheilus of approximately 70 nM. 2. Threshold level and size of egg mass produced by ELH-lysine-amide and bag cell extracts (containing biological ELH) were not significantly different. Latency to lay of recipients of 0.5-4.0 micrograms ELH-lysine-amide (30 +/- 1 min) was significantly longer (P less than 0.05) than for bag cell extract recipients (21 +/- 1 min). 3. ELH-lysine-amide depolarized and activated action potentials in Aplysia buccal neuron B16 in high magnesium, low calcium medium. 4. The lowest concentration of ELH-lysine-amide to activate a supra-threshold response of left and right B16 neurons ranged from 250 nM to 1 microM. 5. Threshold levels for responses to synthetic ELH-lysine-amide and to biological ELH were approximately the same in both egg-laying assay and electrophysiological assay, indicating the likely identity of synthetic and biological ELH. However, the shorter egg-laying latency with bag cell extract suggests that there may be additional factors in the extract that facilitate egg laying.
Ram
J L
JL
Department of Physiology, Wayne State University, Detroit, MI 48201.
Ram
M L
ML
D000818:Animals; D001048:Aplysia / Q000502:physiology*; D005260:Female; D007447:Invertebrate Hormones / Q000494:pharmacology*; D008974:Mollusca; D009046:Motor Neurons / Q000187:drug effects*; D010058:Oviposition / Q000187:drug effects*
D007447:Invertebrate Hormones; C026880:egg-laying hormone, Mollusca