Muneoka Y, Saitoh H
Comp Biochem Physiol C Comp Pharmacol Toxicol. 1986;85(1):207-14. doi: 10.1016/0742-8413(86)90075-7.
In the anterior byssus retractor muscle (ABRM) of Mytilus, low concentrations of FMRFamide (10(-8)-10(-7) M) relax ACh-induced catch-tension, whereas high concentrations (greater than 10(-7) M) cause contraction. To study the structure-activity relations of these actions, a number of peptide analogs of FMRFamide were screened for their biological activities on the ABRM. The structure-activity relations for contraction were different from those for relaxation. Among the peptides tested, FMR-[D-Phe]-amide and gamma 1-MSH substantially antagonized FMRFamide contractions; but only gamma 1-MSH was even slightly antagonistic to FMRFamide-induced relaxation. Relaxations produced by 10(-7) M FMRFamide, or by 10(-5) M FMRFamide-relating relaxing peptides, were markedly depressed by treating the muscle first with 10(-5) M FMRFamide or with 10(-5) M FMRFamide-related contractile peptides. However, contractile agents that are structurally unrelated to FMRFamide, such as 3 X 10(-5) M SCPB and 2 X 10(-2) M caffeine, showed little or no such after-effect on the relaxation. Relaxations in response to submaximal serotonin, dopamine and repetitive electrical pulses of stimulation were not affected by a pretreatment with 10(-5) M FMRFamide. These results suggest that the ABRM of Mytilus has at least two pharmacologically distinct classes of receptors which are capable of being activated by FMRFamide.
在贻贝的前足丝牵缩肌（ABRM）中，低浓度的FMRF酰胺（10^(-8)-10^(-7) M）可舒张乙酰胆碱诱导的捕捉张力，而高浓度（大于10^(-7) M）则会引起收缩。为了研究这些作用的构效关系，筛选了多种FMRF酰胺的肽类似物对ABRM的生物活性。收缩的构效关系与舒张的不同。在所测试的肽中，FMR-[D-苯丙氨酸]-酰胺和γ1-促黑素细胞激素可显著拮抗FMRF酰胺的收缩作用；但只有γ1-促黑素细胞激素对FMRF酰胺诱导的舒张作用有轻微拮抗。先用10^(-5) M FMRF酰胺或10^(-5) M FMRF酰胺相关的收缩肽处理肌肉后，10^(-7) M FMRF酰胺或10^(-5) M FMRF酰胺相关的舒张肽所产生的舒张作用会明显减弱。然而，与FMRF酰胺结构无关的收缩剂，如3×10^(-5) M SCPB和2×10^(-2) M咖啡因，对舒张作用几乎没有这种后效应。对次最大浓度的5-羟色胺、多巴胺和重复性电脉冲刺激的舒张反应不受10^(-5) M FMRF酰胺预处理的影响。这些结果表明，贻贝的ABRM至少有两类药理学上不同的受体，它们能够被FMRF酰胺激活。
