Cephalopods in neuroscience: regulations, research and the 3Rs

Cephalopods have been utilised in neurosci- ence research for more than 100 years particularly because of their phenotypic plasticity, complex and centralised nervous system, tractability for studies of learning and cellular mechanisms of memory (e.g. long-term potentia- tion) and anatomical features facilitating physiological studies (e.g. squid giant axon and synapse). On 1 January 2013, research using any of the about 700 extant species of ‘‘live cephalopods’’ became regulated within the European Union by Directive 2010/63/EU on the ‘‘Protection of Animals used for Scientific Purposes’’, giving cephalopods the same EU legal protection as previously afforded only to vertebrates. The Directive has a number of implications, particularly for neuroscience research. These include: (1) projects will need justification, authorisation from local competent authorities, and be subject to review including a harm-benefit assessment and adherence to the 3Rs princi- ples (Replacement, Refinement and Reduction). (2) To support project evaluation and compliance with the new EU law, guidelines specific to cephalopods will need to be developed, covering capture, transport, handling, housing, care, maintenance, health monitoring, humane anaesthesia, analgesia and euthanasia. (3) Objective criteria need to be developed to identify signs of pain, suffering, distress and lasting harm particularly in the context of their induction by an experimental procedure. Despite diversity of views existing on some of these topics, this paper reviews the above topics and describes the approaches being taken by the cephalopod research community (represented by the authorship) to produce ‘‘guidelines’’ and the potential contribution of neuroscience research to cephalopod welfare

Neuronal Differentiation Factors Cytokines and Synaptic Plasticity

As in the hematopoietic system, the enormous variety of phenotypes in the nervous system arises, in part, through the action of instructive differentiation signals. Such signals include secreted and cell-bound proteins as well as steroid hormones. Since these agents have broad effects on cell proliferation and gene expression in many different tissues, the term cytokines is being adopted for the proteins. The original meaning of that term refers to cell movement, an activity that the present proteins could turn out to share (Cohen et al., 1974; see also Nathan and Sporn, 1991). Our focus here is on the regulation of neuronal gene expression by these factors, particularly the genes that code for neuropeptides and the enzymes that synthesize neurotransmitters, because these are the molecules directly responsible for transmission of information at synapses. We highlight parallels between the control of phenotypic expression in the nervous and hematopoietic systems and between the cytokines involved in the immune response and the response of the nervous system to injury. Attention is also drawn to a potential role for cytokines in synaptic plasticity. For instance, changes in transmission at particular synapses that underlie distinctive behavioral states are often associated with alterations in the expression of the neurotransmitters and neuropeptides employed at those synapses. Such changes in expression can also occur during daily or monthly physiological changes in the body. Moreover, certain paradigms widely used to study the phenomena of learning and memory have, in a few cases, suggested an involvement of cytokines in the plasticity of synaptic transmission