Fig. 5.

Superfusion of the five pyrokinins elicits similar effects on gastric activity in the STNS of the lobster, suggesting that receptors for pyrokinins within the STG bind to pyrokinins indiscriminately. (A) FSPRLamide, (B) PevPKI, (C) PevPK2, (D) CabPK1 and (E) CabPK2. In each panel, the top extracellular recording (mvn) shows the lateral gastric neuron becoming activated during pyrokinin application, whereas the ventricular dilator neuron continues to fire in pyloric time. The middle recording of the dgn shows dorsal gastric neurons changing from firing less-defined gastric bursts with some pyloric characteristics in saline to firing in defined gastric bursts during pyrokinin application. In the recording of the dorsal lateral ventricular nerve (dlvn), the bursts in the LPG neuron became more focused and intense. Recordings are from a single preparation in which the five pyrokinins were applied sequentially, with 1 h washes in saline between each peptide application.