Difficulties and special issues associated with field research in behavioral neuroendocrinology

Classical behavioral neuroendocrinology has focused on a limited number of domestic mammals and birds. The model systems used in these studies represent a very small proportion of the diversity of hormone-behavior interactions found in nature. In the last three decades, an increasing number of researchers have concentrated their efforts on studying behavioral neuroendocrinology of wild animals. Field behavioral neuroendocrinology presents a series of challenges ranging from the design of the experiments to sample preservation and transportation. The constraints of field conditions limit the number of factors that can be controlled for and the questions that can be addressed. On the other side, many behaviors can be studied only in the field, and only a few species can be kept in captivity. Thus, field studies are necessary to understand the complexity and variety of interactions between hormones, brain, and behavior. In this article, we will review some of the peculiarities and challenges of field behavioral neuroendocrinology, including solutions for some of the most commonly encountered technical issues.     

IACUC Challenges in Invertebrate Research

With billions of individuals and possibly hundreds of thousands of genera, invertebrates represent the largest number and greatest diversity of all animals used in research. Although the capacity for nociception is recognized in many invertebrate taxa, researchers and IACUC members are challenged by a lack of clear understanding of invertebrate welfare and by differing standards of moral concern for these taxa. In practice this has led IACUCs to consider invertebrates in two major groups: species worthy of increased moral concern approximating that shown to vertebrate species (this group includes cephalopods and to some extent decapod crustaceans) and all others. This dichotomy has led to differences in how invertebrate research is regulated and documented. This article presents two case studies illustrating specific concerns in invertebrate research protocols and then provides relevant information to address practical IACUC matters related to regulatory and ethical issues, sourcing and record keeping, risk management, assessment of pain and nociception in invertebrates, housing and husbandry, invasive procedures, veterinary care, and humane endpoints.     

Postapproval monitoring and the IACUC

Monitoring of the use of live vertebrate animals in research, teaching, and testing after approval of their use by an institutional animal care and use committee (IACUC) are receiving increased attention in the laboratory animal community. In this article the author provides his opinions on the value of postapproval monitoring (PAM) to the overall self-regulation that is the responsibility of an IACUC. PAM must never supersede or replace federally mandated IACUC responsibilities, but an efficient PAM process can provide significant additional information that enables an institution to be confident that it is meeting both the letter and the spirit of the federal regulations developed to ensure humane animal care. PAM personnel should be excellent communicators and able to maintain a professional demeanor in challenging circumstances. Their knowledge of laboratory animal care, invasive procedures, and regulations will enable them to align the pursuit of scientific research with adherence to these regulations. An effective PAM program involves knowledgeable individuals who can, on behalf of the IACUC, monitor new procedures and personnel and provide IACUC-mandated training or retraining.     

Demonstration of heat production associated with spreading depression in the amphibian retina

Using thin film of synthetic pyroelectric material, polyvinylidene fluoride, sensitive heat-sensors were constructed for the purpose of detecting heat production associated with the phenomenon of spreading depression in isolated amphibian retinae. Measurements with these sensors revealed the existence of large heat production, which closely follows the electrical sign of spreading depression. Studies of the effects of chemical agents known to affect spreading depression have demonstrated the usefulness of heat measurements.     

An innovative IACUC protocol system

The author describes a web-based system that has decreased paper-work and protocol approval time, while making protocols available for viewing by the research community.     

Life history tradeoffs influence mortality associated with the amphibian pathogen Batrachochytrium dendrobatidis

Fatal amphibian chytridiomycosis has typically been associated with the direct costs of infection. However the relationship between exposure to the pathogen, infection and mortality may not be so straightforward. Using results from both field work and experiments we report how exposure of common toads to Batrachochytrium dendrobatidis influences development and survival and how developmental stage influences host responses. Our results show that costs are accrued in a dose dependent manner during the larval stage and are expressed at or soon after metamorphosis. Exposure to B. dendrobatidis always incurs a growth cost for tadpoles and can lead to larval mortality before or soon after metamorphosis even when individuals do not exhibit infection at time of death. In contrast, exposure after metamorphosis almost always results in infection, but body size dictates survival to a greater extent than does dose. These data show that amphibian survival in the face of challenge by an infectious agent is dependent on host condition as well as life history stage. Under current models of climate change, many species of amphibia are predicted to increasingly occur outside their environmental optima. In this case, condition-dependent traits such as we have demonstrated may weigh heavily on species survival.     

Engaging the IACUC through comprehensive training

The IACUC is one of the most important committees at a research institution and plays a critical role in the success of an animal care and use program. It is the responsibility of the institution to provide IACUC members with adequate and appropriate training. The authors explore various IACUC training options.     

Lens crystallin changes associated with amphibian metamorphosis: involvement of a beta-crystallin polypeptide

Lens crystallins isolated from the tadpole and frog lenses were compared with regard to the developmental changes of crystallin compositions. The major changes during the process of metamorphosis were (1) the total contents of alpha- and gamma-crystallins decrease from more than 70% to less than 60% and (2) one of the major beta-crystallin polypeptides increases from less than 1% to about 6% and (3) an amphibian-specific rho-crystallin also increases from about 6% to more than 10% of total soluble proteins of the lens. We have characterized the metamorphosis-dependent beta-crystallin polypeptide by peptide mapping and sequence determination of the protease-digested fragments. This polypeptide showed very high sequence homology to that of the major beta Bp-crystallin chain reported for the mammalian lenses. The changes of the relative abundance of various crystallins and the gradually-elevated levels of the expression of this beta Bp-like crystallin in the developing lens during metamorphosis may also have some bearing on the maintenance of lens stability in the adult frog lenses.