**Abstract**

Marine invertebrate models (squid, sepia, and octopus) made important contributions to description mammals' nervous system. Being a very simple nervous system relatively easy to be manipulated experimentally and visualized by simple microscope or magnifying glass, the giant synapses at stellate ganglion and the large synaptosomes prepared from the squid photoreceptor neurons served as an attractive model to Histology and Anatomy studies. This sophisticated nervous system has elucidated synaptic transmission in detail with their numerous proteins at presynaptic terminal, synaptic vesicle biogenesis, neurotransmitter secretion, vesicle recycling and, allowed the study of postsynaptic complex with their membranes receptors. However, there are few studies with biochemical and molecular approaches, which lead to a better understanding of their physiological functions and verify operation of such nervous system.

**Keywords:** nervous system, axons and giant synapses, synaptosomes and hnRNP proteins
