Relaxing Action of Trp-Nle-Arg-Phe-NH2 on the Anterior Byssus Retractor Muscle of Mytilus

TAKEMOTO Mayumi

SAITOH Hitoshi

MUNEOKA Yojiro

Hiroshima Journal of Medical Sciences

[PISSN] 0018-2052

[EISSN] 2433-7668

[NCID] AA00664312

In the anterior byssus retractor muscle (ABRM) of Mytilus, low concentrations of the molluscan neuropeptide Phe-Met-Arg-Phe-NH2 (FMRFamide) relax ACh-induced catch tension, whereas high concentrations cause contraction. In the present studies the actions of a FMRFamide-analog Trp-Nle-Arg-Phe-NH2 (W-Nle-RFamide) on the ABRM were investigated in order to compare them with those of FMRFamide.
The actions of W-Nle-RFamide were qualitatively similar to those of FMRFamide, but catch-relaxing activity of the former peptide was found to be 10-30 times more potent than that of the latter.
Cytochemical studies showed that FMRFamide-like immunoreactivity was localized to nerve branches in the ABRM and also to neurons in the pedal ganglion.
A peptide which structurally resembles FMRFamide may be involved in the mechanism of the control of relaxation of catch tension in the ABRM of Mytilus.

FMRFamide analog

Relaxation

Catch muscle

医学 [ 490 ]

英語

Hiroshima University School of Medicine

[ISSN] 0018-2052

[NCID] AA00664312

[PMID] 3570846