Summary
Specific temporal relationship (12-hr) of serotonin and dopamine activity was induced by precursor drugs (5-HTP and L-DOPA) in Indian Palm SquirrelFunambulus pennanti during testicular regression phase. This treatment established breeding condition unlike control, which experienced complete atrophy of testes and accessory sex organs.
It is obvious that seasonal testicular regression of Indian Palm Squirrel can be eliminated by 12hr relation of 5-HTP and L-DOPA, which is not a pharmacological effect but actually is an alteration of seasonality in this annually breeding subtropical mammal. It may be concluded that specific phase relation (12-hr) between circadian serotonergic and dopaminergic oscillations may induce breeding condition in regressing gonad of Indian Palm Squirrel during post-reproductive phase of annual gonadal cycle. It is also suggested that inspite of the different environmental factors (photoperiod, humidity etc.) used by different species to time their annual reproduction, basic regulatory mechanism of seasonality appears to be the same, i.e., temporal synergism of neurotransmitter activity.
Similar content being viewed by others
References
Bobillier P, Petitjean F, Salvert D, Ligier M, Sequin S (1975) Differential projections on nucleus raphe dorsalis and nucleus raphe centralis is revealed by autoradiography. Brain Res 85: 205
Bruning JL, Kintz BL (1977) Computational handbook of statistics, 2nd edn. Scott, Foresman, California, Glenview
Chaturvedi CM, Meier AH (1988) Neurotransmitter affecting drugs reset relative photorefractoriness in Japanese quail. LVth Intern Symp Avian Endocrinol Japan, p 122
Chaturvedi CM, Bhatt R (1990) Effect of different temporal relationship of 5-hydroxytryptophan (5-HTP) and L-dihydroxyphenylalanine (L-DOPA) on reproductive and metabolic responses of migratory Red headed bunting (Emberiza bruniceps). J Interdiscipl Cycle Res 21 (2): 129–139
Chaturvedi CM, Jaiwal R (1990) Temporal synergism of neurotransmitter affecting drugs and seasonal reproductive responses of Indian Palm Squirrel,Funambulus pennanti. J Neural Transm 81 (1): 31–40
Elliott JA (1976) Circadian rhythms and photoperiodic time measurement in mammals. Fed Proc 35: 2339–2346
Emata AC, Meier AH, Spieler RE (1985) Temporal variations in gonadal body fast responses to daily injections of 5-hydroxytryptophan (5-HTP) and dihydroxyphenylalanine (DOPA) in the gulf Killifish,Fundulus grandis. J Exp Zool 233: 29–34
Fuxe K, Butcher LL, Engel J (1971) DL-5-hydroxytryptophan-induced changes in central monoamine neurons after peripheral decarboxylase inhibition. J Pharm Pharmacol 23: 420–424
Haldar-Misra C, Srivastava M (1987) Effect of pinealectomy on photoperiodic gonadal response of Indian Palm squirrel,Funambulus pennanti. Can J Zool 65: 833–836
Haldar C, Saxena N (1988) Pineal gland and humidity effects on testicular function of the Indian Palm Squirrel,Funambulus pennanti. J Pineal Res 5: 411–418
Jimenez AE, Voogt JL, Carr LA (1978) L-d, 3-Dihydroxyphenylalanine (L-DOPA) as an inhibitor of prolactin-release. Endocrinology 102: 166–174
Korf J, Venema K, Postema F (1974) Decarboxylation of exogenous L-5-hydroxytryptophan after destruction of the cerebral raphe system. J Neurochem 23: 249–252
Miller LJ, Meier AH (1983) Circadian neurotransmitter activity resets the endogenous annual cycle in a migratory sparrow. J Interdisc Cycle Res 14: 85–94
Reiter RJ (1973) Pineal control of a seasonal reproductive rhythm in male golden hamsters exposed to natural daylight and temperature. Endocrinology 92: 423–430
Reiter RJ (1975) Exogenous and endogenous control of annual reproductive cycle in male golden hamsters: participation of the pineal gland. J Exp Zool 191: 111–120
Shindo H, Komai R, Tanaka K, Makjima E, Miyakoshi N (1973) Studies on the metabolism of D- and L-isomers, 3,4-dihydroxyphenylalanine (DOPA): IV urinary and tissue metabolism of D- and L-DOPA 14C after intravenous and oral administration to rats. Chem Pharm Bull 21: 826–836
Stetson MH, Watson-Whitmyra M, Matt KS (1977) Termination of photorefractoriness in golden hamsters — photoperiodic requirements. J Exp Zool 202: 81–88
Wilson JM, Meier AH (1989) Resetting the annual cycle with timed daily injections of 5-hydroxytryptophan and L-dihydroxyphenylaline in syrian hamsters. Chronobiology Intern 6: 113–132
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Jaiwal, R., Chaturvedi, C.M. Elimination of testicular regression by 12-hr temporal relationship of serotonergic and dopaminergic activity in Indian Palm Squirrel,Funambulus pennanti . J. Neural Transmission 84, 45–52 (1991). https://doi.org/10.1007/BF01249108
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF01249108