required reading:
Gammie SC, Truman JW (1997). Neuropeptide Hierarchies and the Activation of Sequential Motor Behaviors. in the Hawkmoth, Manduca sexta. J Neurosci 17(11):4389–4397.
pdf-file
required reading:
Gammie SC,
Truman JW (1997). Neuropeptide Hierarchies and the Activation of Sequential
Motor Behaviors. in the Hawkmoth, Manduca sexta. J Neurosci 17(11):4389–4397.
pdf-file
questions:
1. What are the two phases involved
in shedding the old cuticle? What does each achieve?
2. How were the samples prepared and recorded from?
3. Briefly describe the immunocytochemistry techniques to assess cGMP levels.
4. What happened when they added CCAP to the isolated abdominal ganglia? to
sheathed vs. unsheathed ganglia? Characterize the response- (phasic vs. tonic,
anterior progression vs. metachronous activity, response duration, reversible
or not, concentration dependent). How do they know the response they get corresponds
to ecdysis?
5. What was the effect of ETH on the whole isolated CNS vs. the desheathed abdominal
CNS? How did the response to ETH differ from that to CCAP in some of the above
characteristics? What does the use of isolated abdominal ganglia tell us about
the role of ETH and CCAP?
6. How do ETH and CCAP interact? What if ETH is applied before CCAP? What happens
if CCAP is applied before ETH? What do these results suggest?
7. How does developmental sensitivity differ for the two compounds? Why may
there not need to be a limited window of sensitivity for CCAP?
8. What is the role of cGMP? How did cGMP levels differ between whole vs. isolated
abdominal CNSs exposed to ETH? What about levels from isolated abdominal CNSs
exposed to CCAP? What does this suggest? What did the CCAP immunochemistry show?
How do CCAP levels of girdled larvae compare to those of normal larvae?
9. How do the larvae achieve both phases of ecdysis sequentially given that
ETH both initiates pre-ecdysis behavior and induces the release of EH which
leads to CCAP release and the termination of pre-ecdysis behavior?
PDF-file of power point lecture (about 1.4 MB)
background reading:
Truman JW, Riddiford LM (2002). Endocrine
insights into the evolution of metamorphosis in insects. Annu. Rev. Entomol.
47:467–500. pdf-file
Links:
