Abstract
An hypothesis that repeated stress results in central changes in α2-adrenoceptor sensitivity was investigated using a behavioural test. Stressed (immobilisation for 2 h/day for 7 days) and unstressed rats from the RHA/iop and RLA/iop strains were tested for the sedative effects of the α2-adrenoceptor agonist clonidine on Y-maze behaviour. The measures used were number of lines crossed, arm entries and rearing. The stressed animals showed higher scores for line crossings and rearing; but the only significant difference between the strains was for rearing, which was higher for RHA/iop. Clonidine significantly depressed all the measures of activity. However, there was no evidence of an interaction of the drug with stress for any of the measures. It is concluded that neither repeated stress nor genetic differences in the ability to cope with stress influence the behavioural effects of clonidine. This suggests that stress responses are not related to the central α2-adrenoceptor system.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Anisman H, Zacharko RM (1982) Depression: The predisposing influence of stress. Behav Brain Sci 5:89–137
Antelman SM, Caggiula AR (1977) Norepinephrine-dopamine interactions and behavior. Science 195:646–653
Bignami G (1965) Selection for high rates and low rates of avoidance conditioning. Anim Behav 13:221–227
Cohen RM, Campbell IC, Cohen MR, Torda T, Pickar D, Siever LJ, Murphey DL (1980) Presynaptic noradrenergic regulation during depression and antidepressant drug treatment. Psychiatr Res 3:93–105
Delacour J, Coulon JF, David JC, Guenaire C (1983) Brain octopamine and strain differences in avoidance behavior. Brain Res 288:169–176
Drew GM, Gower AJ, Marriot AS (1977) Pharmacological characterisation of alpha-adrenoceptors which mediate clonidine induced sedation. Br J Pharmacol 61:468
Driscoll P, Bättig K (1982) Behavioral, emotional and neurochemical profiles of rats selected for extreme differences in active, two-way avoidance performance. In: Lieblich I (ed) Genetics of the Brain. Elsevier, Amsterdam, pp 95–123
Durcan MJ, Fulker DW, Campbell IC (1984) Differences in the stereotypy response but not the hypomotility response to apomorphine in the Roman High and Low Avoiding strains of rats. Psychopharmacology 82:215–220
Heal DJ, Akagi H, Bowdler JM, Green AR (1981) Repeated electroconvulsive shock attenuates clonidine-induced hypoactivity in rodents. Eur J Pharmacol 75:231–237
Hewitt JK, Fulker DW (1984) Using the triple test cross to investigate the genetics of behavior in wild populations: III activity and reactivity. Behav Genet 14:125–135
Iversen SD (1977) Brain dopamine systems and behavior. In: Iversen LL, Iversen SD, Snyder SH (eds) Handbook of psychopharmacology Vol 8. Plenum Press, New York, London, pp 333–384
Langer SZ (1981) Presynaptic regulation of the release of catecholamines. Pharmacol Rev 32:337–362
Lynch M, Littleton J, McKernan RM, Durcan MJ, McMillan T, Campbell IC (1983) α-Adrenoceptor number and function in rat cortex after ethanol and immobilisation stress. Brain Res 288:145–149
McLennan AJ, Maier SF (1983) Coping and the stress-induced potentiation of stimulant stereotypy in the rat. Science 219:1091–1093
Nomura Y, Oki K, Segawa T (1980) Pharmacological characterization of central α-adrenoceptors which mediate clonidine-induced locomotor activity in the developing rat. Naunyn-Schmiedeberg's Arch Pharmacol 311:41–44
Spyraki C, Fibiger HC (1980) Functional evidence for subsensitivity of noradrenergic alpha2 receptors after chronic desipramine treatment. Life Sci 27:1863–1867
Starke K (1977) Regulation of noradrenaline release by presynaptic receptor systems. Rev Physiol Biochem Pharmacol 77:1–124
Strombom U (1975) Effects of low doses of catecholamine receptor agonists on exploration in mice. J Neural Transm 37:229–235
Strombom U (1976) Catecholamine receptor agonists: effects on motor activity and rate of tyrosine hydroxylation in mouse brain. Naunyn-Schmiedeberg's Arch Pharmacol 292:167–176
Stone EA (1981) Mechanism of stress-induced subsensitivity to norepinephrine. Pharmacol Biochem Behav 14:719–723
Stone EA, Platt JE (1982) Brain adrenergic receptors and resistance to stress. Brain Res 237:405–414
Torda T, Yamaguchi I, Hirata F, Kopin IH, Axelrod J (1981) Mepacrine treatment prevents immobilization induced desensitization of beta adrenergic receptors in rat hypothalamus and brain stem. Brain Res 205:441–444
Tsuda A, Tanaka M, Kohno Y, Ida Y, Joaki Y, Iimori K, Nakagawa R, Nishikawa T, Nagasaki N (1983) Daily increase in noradrenaline turnover in brain regions of activity-stressed rats. Pharmacol Biochem Behav 19:393–396
U'Prichard DC, Bechtel WD, Rouot BM, Snyder SH (1979) Multiple apparent α-noradrenergic receptor binding sites in rat brain: Effect of 6-hydroxydopamine. Mol Pharmacol 16:47–60
Zebrowska-Lupina I, Przegalinski S, Kleinrock Z (1977) Clonidine-induced locomotor hyperactivity in rats: the role of central postsynaptic alpha-adrenoceptors. Naunyn-Schmiedeberg's Arch Pharmacol 297:227–231
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Durcan, M.J., Campbell, I.C. & Chitkara, B. Clonidine induced sedation is not altered by repeated stress in the RHA/iop and RLA/iop strains of rats. Psychopharmacology 85, 102–105 (1985). https://doi.org/10.1007/BF00427331
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00427331