Abstract
Daily injections of 5-HTP (5-hydroxytryptophan, serotonin precursor) and L-DOPA (L-Dihydroxyphenylalanine, dopamine precursor) given 8 hour apart inhibited normal testicular growth in seasonally breeding Indian Palm Squirrel, Funambuluspennanti leading to complete gonadal atrophy, which was maintained till the end of the study. HCG administration induced higher degree of gonadal development but, when the two treatments (HCG + 8 hr relationship of 5-HTP and L-DOPA) were given simultaneously no significant difference was observed compared to control. Results indicate that induced suppression of gonadal function in a fashion similar to seasonal regression leading to non-breeding condition is the consequence of specific phase relationship (8 hr) between serotonergic and dopaminergic activities and not due to Serotonin or dopamine alone. This suggestion gets support from the finding that gonadal condition of squirrels receiving only 5-HTP (5-HTP control) or L-DOPA (DOPA control) was not different from control and exhibited normal testicular growth. It also seems that neurotransmitter precursor drugs given 8 hr apart possibly inhibited the activity of neuroendocrine-gonadal axis since this effect was overpowered by stimulatory effect of gonadotrophin. The findings strongly support the hypothesis that specific phase relation of circadian serotonergic and dopaminergic oscillations account for seasonal reproductive conditions.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 53-60 |
| Number of pages | 8 |
| Journal | Journal of Neural Transmission |
| Volume | 88 |
| Issue number | 1 |
| DOIs | |
| State | Published - Feb 1 1992 |
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Keywords
- 5-hydroxytryptophan
- L-dihydroxyphenylalanine
- Neurotransmitter
- dopamine
- gonadotrophin
- seasonal breeding cycle
- serotonin
- testis
ASJC Scopus subject areas
- Neurology
- Clinical Neurology
- Psychiatry and Mental health
- Biological Psychiatry
Cite this
Suppression of annual testicular development in Indian Palm Squirrel, Funambulus pennanti by 8 hr temporal relationship of serotonin and dopamine precursor drugs. / Chaturvedi, C. M.; Singh, A. B.
In: Journal of Neural Transmission, Vol. 88, No. 1, 01.02.1992, p. 53-60.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Suppression of annual testicular development in Indian Palm Squirrel, Funambulus pennanti by 8 hr temporal relationship of serotonin and dopamine precursor drugs
AU - Chaturvedi, C. M.
AU - Singh, A. B.
PY - 1992/2/1
Y1 - 1992/2/1
N2 - Daily injections of 5-HTP (5-hydroxytryptophan, serotonin precursor) and L-DOPA (L-Dihydroxyphenylalanine, dopamine precursor) given 8 hour apart inhibited normal testicular growth in seasonally breeding Indian Palm Squirrel, Funambuluspennanti leading to complete gonadal atrophy, which was maintained till the end of the study. HCG administration induced higher degree of gonadal development but, when the two treatments (HCG + 8 hr relationship of 5-HTP and L-DOPA) were given simultaneously no significant difference was observed compared to control. Results indicate that induced suppression of gonadal function in a fashion similar to seasonal regression leading to non-breeding condition is the consequence of specific phase relationship (8 hr) between serotonergic and dopaminergic activities and not due to Serotonin or dopamine alone. This suggestion gets support from the finding that gonadal condition of squirrels receiving only 5-HTP (5-HTP control) or L-DOPA (DOPA control) was not different from control and exhibited normal testicular growth. It also seems that neurotransmitter precursor drugs given 8 hr apart possibly inhibited the activity of neuroendocrine-gonadal axis since this effect was overpowered by stimulatory effect of gonadotrophin. The findings strongly support the hypothesis that specific phase relation of circadian serotonergic and dopaminergic oscillations account for seasonal reproductive conditions.
AB - Daily injections of 5-HTP (5-hydroxytryptophan, serotonin precursor) and L-DOPA (L-Dihydroxyphenylalanine, dopamine precursor) given 8 hour apart inhibited normal testicular growth in seasonally breeding Indian Palm Squirrel, Funambuluspennanti leading to complete gonadal atrophy, which was maintained till the end of the study. HCG administration induced higher degree of gonadal development but, when the two treatments (HCG + 8 hr relationship of 5-HTP and L-DOPA) were given simultaneously no significant difference was observed compared to control. Results indicate that induced suppression of gonadal function in a fashion similar to seasonal regression leading to non-breeding condition is the consequence of specific phase relationship (8 hr) between serotonergic and dopaminergic activities and not due to Serotonin or dopamine alone. This suggestion gets support from the finding that gonadal condition of squirrels receiving only 5-HTP (5-HTP control) or L-DOPA (DOPA control) was not different from control and exhibited normal testicular growth. It also seems that neurotransmitter precursor drugs given 8 hr apart possibly inhibited the activity of neuroendocrine-gonadal axis since this effect was overpowered by stimulatory effect of gonadotrophin. The findings strongly support the hypothesis that specific phase relation of circadian serotonergic and dopaminergic oscillations account for seasonal reproductive conditions.
KW - 5-hydroxytryptophan
KW - L-dihydroxyphenylalanine
KW - Neurotransmitter
KW - dopamine
KW - gonadotrophin
KW - seasonal breeding cycle
KW - serotonin
KW - testis
UR - http://www.scopus.com/inward/record.url?scp=0026586610&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0026586610&partnerID=8YFLogxK
U2 - 10.1007/BF01245036
DO - 10.1007/BF01245036
M3 - Article
C2 - 1575953
AN - SCOPUS:0026586610
VL - 88
SP - 53
EP - 60
JO - Journal of Neural Transmission
JF - Journal of Neural Transmission
SN - 0300-9564
IS - 1
ER -