DIFFERENTIAL EFFECTS OF CRH INFUSION INTO THE CENTRAL NUCLEUS OF THE AMYGDALA IN THE ROMAN HIGH-AVOIDANCE AND LOW-AVOIDANCE RATS
Section snippets
INTRODUCTION
Corticotropin-releasing hormone (CRH) is a neuropeptide that has been widely associated with several behavioural and physiological aspects of stress (Dunn and Berridge, 1990, Owens and Nemeroff, 1991). In addition to its activating effects on the hypothalamus–pituitary–adrenal axis, intracerebroventricular (icv) injection of CRH produces elevations of heart-rate and blood pressure, as well as rises in plasma catecholamine and glucose levels (Bakke et al., 1990, Brown et al., 1982, Brown and
Animals
Twenty-three RHA/Verh and 23 RLA/Verh (male, Wistar-derived) rats, weighing 280–380 g at the beginning of the experiment, were used. Animals were obtained from the breeding colony at the Animal Science Institute (Zurich, Switzerland) at the age of 5–8 weeks. The rats were housed in groups of five animals per cage and left undisturbed until the age of 14 weeks in a temperature controlled room (20±1°C) with a 12-h light–dark cycle (lights on from 0800 to 2000h). Three days before surgery the
Histology
Following histological examination, five out of the 46 animals used had to be excluded from further analysis because of improper bilateral cannula placement. The cannula tips had to be localised just above or entering the dorsal edge of the CeA.
Cardiac responses
Fig. 1 shows the change in heart-rate before, during and after infusion of 30 ng of CRH or aCSF into the CeA, compared with basal values of heart-rate (t=−10 and −1 min). No significant differences were found in basal heart-rate values of all the groups
DISCUSSION
The major finding of the present study is that local CRH microinfusion into the CeA of RHA/Verh and RLA/Verh rats resulted in distinctly different behavioural, physiological and neurobiological responses under stress-free conditions.
RHA/Verh rats responded to this treatment with an increase in heart-rate which lasted for at least 17 min. This was accompanied by decreased resting/sleeping indicating an increase in overall behavioral activation. The same treatment induced only a slight behavioral
Acknowledgements
The authors wish to thank Dr P. Driscoll for kindly providing the RHA/Verh and RLA/Verh rats. This study is financially supported by the Council of Geological and Biological Sciences of the Netherlands Organization for Scientific Research within the research program ‘Neuropeptides and Behaviour’, SLW-BION Grant no: 805-16-206.
References (48)
- Andreae, L. C. and Herbert, J. (1993) Expression of c-fos in restricted areas of the basal forebrain and brainstem...
- Aubry, J. M., Bartanusz, V., Driscoll, P., Schulz, P., Steimer, T. and Kiss, J. Z. (1995) Corticotropin-releasing...
- Bakke, H. K., Bogsnes, A. and Murison, R. (1990) Studies on the interaction between icv effects of CRF and CNS...
- Berridge, C. W. and Dunn, A. J. (1987) Corticotropin-releasing factor reverses the stress-induced changes of...
- Bohus, B. (1974) Telemetred heart rate responses of the rat during free and learned behavior. Biotelemetry 1,...
- Bohus, B., Benus, R. F., Fokkema, D. S., Koolhaas, J. M., Nyakas, C., van Oortmerssen, G. A., Prins, A. J. A., de...
- Britton, D. R., Koob, G. F., Rivier, J. and Vale, W. (1982) Intraventricular corticotropin-releasing factor enhances...
- Brown, M. R. and Fisher, L. A. (1985) Corticotropin-releasing factor: effects on the autonomic nervous system and...
- Brown, M. R., Fisher, L. A., Spiess, J., Rivier, C., Rivier, J. and Vale, W. (1982) Corticotropin-releasing factor:...
- Castanon, N., Dulluc, J., LeMoal, M. and Mormede, P. (1994) Maturation of the behavioral and neuroendocrine differences...
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