Abstract
Unfavorable conditions under which children grow up may contribute significantly to the development of psychiatric abnormalities in adult life. We studied the effects of overcrowding at an early age and how it may result in anxiety later in life. Sprague-Dawley rats were housed 10 animals per cage, from birth until 4 weeks post-weaning. Rats housed 3 per cage served as controls. The Elevated Plus maze was used to determine their anxious behavior. Thereafter, the serotonergic system in the hippocampus was investigated. Overcrowded rats were significantly more anxious than controls. The number of 5HT-la receptors in the hippocampus decreased significantly and their affinity for the ligand, OH-DPAT, increased significantly. There was no significant difference in the hippocampal levels of serotonin between overcrowded rats and controls. Our study shows that overcrowding during childhood can result in anxious behavior and that the serotonergic system appears to play a role in its manifestation.
Similar content being viewed by others
REFERENCES
Albinsson, A., Palazidou, E., Stephenson, J., and Andersson, G. (1994). Involvement of the 5-HT2 receptor in the 5-HT receptor-mediated stimulation of prolactin release. Eur. J. Pharmacol. 14:251(2–3):157-61.
Almqvist, E.W., Bloch, M., Brinkman, R., Craufurd, D., and Hayden, M.R. (1999). A worldwide assessment of the frequency of suicide, suicide attempts, or psychiatric hospitalization after predictive testing for Huntington disease. Am. J. Hum. Genet. 64(5):1293-304.
Armario, A., Castellanos, J.M., and Balasch, J. (1984). Effect of overcrowding on emotional reactivity in male rats. Neuroendocrinology 39:330-333.
Bugajski, J., Gadek-Michalska, A., Borycz, J., and Wieczorek, E. (1994). Effect of crowding on corticosterone responses to central adrenergic stimulation. Agents-Actions 41 Spec No:C73-4.
Chorpita, B.F., and Barlow, D.H. (1998). The development of anxiety: the role of control in the early environment. Psychol. Bul. 124(1):3-21.
Gadek-Michalska, A., Borycz, J., and Bugajski, J. (1994). Pituitary-adrenocortical responsiveness to histaminergic stimulation during social stress of crowding in rats. Agents-Actions 41 Spec No: C80-1.
Hall, M.D., Emerit, M.B., Pichat, L., Hamon, M., and Gozlan, H. (1985). [3H] 8-Hydroxy-2-(Di-n-Propylamino) Tetralin binding to pre-and postsynaptic 5-Hydroxytryptamine sites in various regions of the rat brain. J. Neurochem. 44:1685-1695.
Janus, K. (1987). Effects of early separation of young rats from the mother on their open-field behavior. Physiol. Behav. 40(6): 711-5.
Ladd, C.O., Owens, M.J., and Nemeroff, C.B. (1996). Persistent changes in corticotropin-releasing factor neuronal systems induced by maternal deprivation. Endocrinology 137(4):1212-8.
Lopez, J.F., Chalmers, D.T., Little, K.Y., and Watson, S.J. (1998). Regulation of serotonin 1A, glucocorticoid, and mineralocorticoid receptor in rat and human hippocampus: Implications for the neurobiology of depression. Biol. Psychiatry 15;43(8): 547-73.
Lowry, O.H., Rosebrough, N.J., and Farr, A.L. (1951). Protein measurement with the folin phenol reagent. J. Biochem. 193:265-275.
Matthews, K., Wilkinson, L.S., and Robbins, T.W. (1996). Repeated maternal separation of preweanling rats attenuates behavioral responses to primary and conditioned incentives in adulthood. Physiol.Behav. 59(1):99-107.
Millan, M.J., Hjorth, S., Samanin, R., Schreibe., R., Jaffard, R., De-Ladonchamps, B., Veiga, S., Goument, B., Peglion, J.L., Spedding, M., and Brocco, M. S. (1997). 15535, a novel benzodioxopiperazine ligand of serotonin (5-HT) 1A receptors: II. Modulation of hippocampal serotonin release in relation to potential anxiolytic properties. J. Pharmacol. Exp. Ther. 282(1):148-61.
Miller, G.I. (1959). Protein determination for large numbers of samples. Anal. Chem. 31:964.
Ninan, P.T. (1999). The functional anatomy, neurochemistry, and pharmacology of anxiety. J. Clin. Psychiatry. 60 Suppl 22:12-7.
Parks, C.L., Robinson, P.S., Sibille, E., Shenk, T., and Toth, M. (1998). Increased anxiety of mice lacking the serotonin 1A receptor. Proc.Natl.Acad.Sci.U.S.A. 95(18):10734-9.
Pellow, S., Chopin, P., File, S.E., and Briley, M. (1985). Validation of open:closed arm entries in an Elevated Plus-maze as a measure of anxiety in the rat. J. Neurosci. Methods 14:159-167.
Rodgers, R.J., and Dalvi, A. (1997). Anxiety, defense and the elevated plus-maze. Neurosci-Biobehav-Rev. 21(6):801-10.
Sadowski, H., Ugarte, B., Kolvin, I., Kaplan, C., and Barnes, J. (1999). Early life family disadvantages and major depression in adulthood. Br. J. Psychiatry 174:112-20.
Sandanger, I., Moum, T., Ingebrigtsen, G., Sorensen, T., Dalgard, O.S., and Bruusgaard, D. (1999). The meaning and significance of caseness: the Hopkins Symptom Checklist-25 and the Composite International Diagnostic Interview II. Soc. Psychiatry Psychiatr. Epidemiol. 34(1): 53-9.
Spivak, B., Vered, Y., Yoran-Hegesh, R., Averbuch, E., Mester, R., Graf, E. and Weizman, A. (1999). Circulatory levels of catecholamines, serotonin and lipids in attention deficit hyperactivity disorder. Acta. Psychiatr. Scand. 99(4):300-4.
Stefanski, R., Palejko, W., Kostowski, W., and Plaznik, A. (1992). The comparison of benzodiazepine derivatives and serotonergic agonists and antagonists in two animal models of anxiety. Neuropharmacology 31(12):1251-8.
Subhash, M.N., Srinivas, B.N., Vinod, K.Y., and Jagadeesh, S. (2000). Modulation of 5-HT1A receptor mediated response by fluoxetine in rat brain. J. Neural Transm. 107(3):377-87.
Taylor, D.P. (1990). Serotonin agents in anxiety. In: Whitikar-Azmitia, P.M., and Peroutka, S.J., eds. The Neuropharmacology of Serotonin. Vol. 600. New York: Annals of the New York academy of Sciences, 1545-573.
Wigger, A., and Neumann, I.D. (1999). Periodic maternal deprivation induces gender-dependent alterations in behavioral and neuroendocrine responses to emotional stress in adult rats. Physiol. Behav. 66(2):293-302.
Wright, I.K., Upton, N., and Marsden, C.A. (1992). Effect of established and putative anxiolytics on extracellular 5-HT and 5-HIAA in the ventral hippocampus of rats during behavior on the elevated X-maze. Psychopharmacology Berl. 109(3):338-46.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Daniels, W.M., Pietersen, C.Y., Carstens, M.E. et al. Overcrowding Induces Anxiety and Causes Loss of Serotonin 5HT-1a Receptors in Rats. Metab Brain Dis 15, 287–295 (2000). https://doi.org/10.1023/A:1011123208674
Issue Date:
DOI: https://doi.org/10.1023/A:1011123208674