Smith S A, Nason J, Croll R P
Department of Biology, Dalhousis University, Halifax, Nova Scotia, Canada.
Neuropeptides. 1997 Apr;31(2):155-65. doi: 10.1016/s0143-4179(97)90085-8.
In pulmonate gastropods, the peptide, Ala-Pro-Gly-Trp-NH2 (APGWamide), appears to be located nearly exclusively in the neural circuitry controlling the male reproductive organs. This neuropeptide and related neuropeptides are also present and apparently bioactive in bivalve molluscs, although their physiological role in these latter animals is unknown. The present report uses immunohistochemistry to examine the distribution of APGWamide and/or related peptides within the tissues of the deep sea scallop, Placopecten magellanicus. Much of the APGWamide-like immunoreactivity (APGWa-LIR) was detected in the central nervous system (CNS) of both juvenile and adult scallops, where it was concentrated in the cerebral, pedal and parietovisceral ganglia, particularly in the cortex of ganglionic cells and their axons which extend into the central neuropilar region. APGWa-LIR was also detected in the nerves ramifying from these ganglia. In addition, strong APGWa-LIR was localized in what appeared to be axonal terminals within peripheral tissues including the striated adductor muscle, foot, gills, labial palps, lips, tentacles and gonads of the juvenile scallops. The presence of APGWa-LIR was also confirmed in the gonads of adults of both sexes. Cursory examinations of the CNS of the mussel, Mytilus edulis, and the oyster, Crassostrea virginica, revealed the presence of APGWa-LIR in cell bodies and processes in these bivalve species as well. It is concluded that APGWamide and/or related peptides are probably important neurotransmitters and/or neuromodulators of several central and peripheral functions in P. magellanicus and other bivalves. Future work must focus on the possible roles for APGWamide in the physiological processes of these and other bivalve species.
在肺螺亚纲腹足类动物中，肽Ala-Pro-Gly-Trp-NH2（APGW酰胺）似乎几乎仅存在于控制雄性生殖器官的神经回路中。这种神经肽及相关神经肽在双壳贝类中也存在且显然具有生物活性，尽管它们在这些动物中的生理作用尚不清楚。本报告利用免疫组织化学方法研究了深海扇贝（Placopecten magellanicus）组织内APGW酰胺和/或相关肽的分布情况。在幼年和成年扇贝的中枢神经系统（CNS）中均检测到了大量的APGW酰胺样免疫反应性（APGWa-LIR），其集中在脑、足和脏壁神经节中，尤其集中在神经节细胞的皮质及其延伸至中枢神经纤维区域的轴突中。在从这些神经节分支出来的神经中也检测到了APGWa-LIR。此外，在幼年扇贝的外周组织（包括横纹闭壳肌、足、鳃、唇瓣、唇、触手和性腺）中，强烈的APGWa-LIR定位于看似轴突终末的部位。在成年雌雄扇贝的性腺中也证实了APGWa-LIR的存在。对贻贝（Mytilus edulis）和弗吉尼亚牡蛎（Crassostrea virginica）的中枢神经系统进行的初步检查显示，在这些双壳类动物的细胞体和突起中也存在APGWa-LIR。研究得出结论，APGW酰胺和/或相关肽可能是麦哲伦扇贝及其他双壳类动物中几种中枢和外周功能的重要神经递质和/或神经调节剂。未来的工作必须聚焦于APGW酰胺在这些及其他双壳类动物生理过程中的可能作用。
