Structure-activity relationship studies on the endogenous neuroactive tetrapeptide achatin-I on giant neurons of Achatina fulica Ferussac.
The structure-activity relationships of achatin-I, a neuroactive peptide containing a D-phenylalanine residue, for producing excitatory effects on three different types of Achatina neurons, PON, TAN and d-RCDN, were studied under the voltage clamp method. Of the peptides examined, only Gly-Gly-D-Phe-L-Ala-L-Asp (IV). D-Phe-L-Ala-L-Asp (V) and Gly-D-Phe-L-Ala-L-Asn (XVI) produced an inward current with increased membrane conductance similar to achatin-1 (I). The structure-activity relationship was essentially the same for the three Achatina neuron types. The equiactive molar ratios (EMRs) of the active peptides vs. achatin-I (I) were calculated from their dose-response curves: 8 - 60 for Gly-Gly-DPhe-L-Ala-L-Asp (IV), 200 - greater than 250 for D-Phe-L-Ala-L-Asp (V) and greater than 200 for Gly-D-Phe-L-Ala-L-Asn (XVI). These values indicate that the achatin-I receptor in the Achatina neurons is highly structure-specific.
Kim
K H
KH
Department of Physiology, Gifu University School of Medicine, Japan.
Takeuchi
H
H
Kamatani
Y
Y
Minakata
H
H
Nomoto
K
K
D000595:Amino Acid Sequence; D000818:Animals; D004305:Dose-Response Relationship, Drug; D008969:Molecular Sequence Data; D009474:Neurons / Q000187:drug effects*; D009479:Neuropeptides / Q000737:chemistry / Q000494:pharmacology*; D018377:Neurotransmitter Agents / Q000737:chemistry / Q000494:pharmacology*; D012908:Snails; D013329:Structure-Activity Relationship
D009479:Neuropeptides; D018377:Neurotransmitter Agents; C059927:achatin I