Brain opioid receptor density reflects behavioral and heart rate responses in pigs
| Autor: | Victor M. Wiegant, Willem G.P. Schouten, L.W.S Loijens, P.R. Wiepkema |
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| Rok vydání: | 2002 |
| Předmět: |
Restraint
Physical medicine.medical_specialty Institute of Agricultural and Environmental Engineering Swine medicine.drug_class Hypothalamus Instituut voor Mechanisatie Hippocampus Naloxone binding Experimental and Cognitive Psychology (+)-Naloxone Motor Activity Open field Behavioral Neuroscience Instituut voor Mechanisatie Arbeid en Gebouwen Heart Rate Opioid receptor Internal medicine Adaptation Psychological medicine Animals Chronic stress Receptor Arbeid en Gebouwen Endogenous opioid Brain Chemistry Behavior Animal Feeding Behavior Chair Ethology Coping style Kinetics Leerstoelgroep Ethologie Stereotypy (non-human) Endocrinology Receptors Opioid Individual differences WIAS Regression Analysis Female Vocalization Animal Psychology |
| Zdroj: | Physiology and Behavior 76 (2002) Physiology and Behavior, 76, 579-587 |
| ISSN: | 0031-9384 |
| DOI: | 10.1016/s0031-9384(02)00729-1 |
| Popis: | Results from our previous research indicate that long-term tether-housed pigs with high and low levels of stereotypies show differences in the density of endogenous opioid receptors in the hippocampus and hypothalamus. It was not clear whether differences in opioid receptor density were induced by the chronic stress of tether housing or stereotypy performance, or were already present before the animals were tethered. The latter possibility was tested in the present experiment. We used a group of 18 nonstereotyping pigs that had no experience with tether housing and investigated whether the animals differed in the density of endogenous opioid receptors in the brain and, if so, whether these differences were related to the animals' reactions to acute challenges. The pigs were subjected to two tests: an open field test and a tethering test. Behavioral reactions as well as heart rate responses were measured. Opioid receptor densities were determined postmortem in the hippocampus and hypothalamus using a membrane binding assay with [(3)H]naloxone as a ligand. Animals differed widely in their responses to the two tests. In support of our hypothesis, we found a relationship between behavioral and heart rate responses and densities of naloxone binding sites in the hippocampus and hypothalamus. The data suggest that endogenous opioid systems in the brain contribute to differences in stress responding between individual pigs. |
| Databáze: | OpenAIRE |
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