About a snail, a toad, and rodents: animal models for adaptation research

Abstract

Neural adaptation mechanisms have many similarities throughout the animal kingdom, enabling to study fundamentals of human adaptation in selected animal models with experimental approaches that are impossible to apply in man. This will be illustrated by reviewing research on three of such animal models, viz. (1) the egg-laying behavior of a snail, Lymnaea stagnalis: how one neuron type controls behavior, (2) adaptation to the ambient light condition by a toad, Xenopus laevis: how a neuroendocrine cell integrates complex external and neural inputs, and (3) stress, feeding, and depression in rodents: how a neuronal network co-ordinates different but related complex behaviors. Special attention is being paid to the actions of neurochemical messengers, such as neuropeptide Y, urocortin 1, and brain-derived neurotrophic factor. While awaiting new technological developments to study the living human brain at the cellular and molecular levels, continuing progress in the insight in the functioning of human adaptation mechanisms may be expected from neuroendocrine research using invertebrate and vertebrate animal models.

From frog integument to human skin: dermatological perspectives from frog skin biology

“…This process is very pronounced in X. laevis , where it has been studied extensively (e.g. Roubos et al , 2010 a , b ; Jenks et al , ). On a black background, α‐MSH is released from neuroendocrine melanotrope cells in the pituitary pars intermedia (Fig.…”

“…) (e.g. Tonon et al , ; van Wijk, Meijer & Roubos, ; Roubos et al , 2010 a , b ; Jenks et al , ). These messengers are produced in various parts of the brain and released from the neural pituitary lobe towards the melanotrope cells or reach them directly via synaptic contacts, permitting the animal to adjust skin pigmentation not only to ambient light condition, by γ‐aminobutyric acid (GABA), dopamine and NPY (Tonon et al , , ; Adjeroud et al , ; de Rijk, van Strien & Roubos, ; Tuinhof et al , ) but also in response to stressful situations, and following changes in ambient temperature and subsequent signalling by TRH (Tonosaki et al , ).…”

“…Research into the biology of frogs is currently very extensive, encompassing numerous fields, such as cell biology, embryology, neuroscience, (neuro)endocrinology, ecology, genetics, behavioural science, evolution, public health, and conservation biology (e.g. Lutz, Blodt & Kloas, ; Vaudry et al , ; Hayes et al , ; Roubos et al , 2010 a ). Frogs belong to the order Anura, which also includes toads.…”

Plasticity of melanotrope cell regulations in Xenopus laevis

“…The neuroendocrine melanotrope cell in the pars intermedia of the pituitary gland of the amphibian Xenopus laevis is a well‐established experimental model to investigate aspects of neuroplasticity in a physiological context, because the secretion of α‐melanophore‐stimulating hormone (α‐MSH) can be physiologically manipulated and is readily activated by putting the animal on a dark background (Roubos et al. , 2005, 2010; Jenks et al.…”

“…Release of α‐MSH stimulates the black pigment melanin in the skin melanophores to disperse, causing darkening of the skin. In the absence of α‐MSH the pigment granules remain situated around the melanophore cell nucleus, resulting in a pale aspect of the skin (for reviews see Roubos et al. , 2005, 2010; Jenks et al.…”