Showing papers by "Chandra Mohini Chaturvedi published in 2006"
TL;DR: The findings indicate that 12-hr temporal interaction of 5-HTP and L-DOPA administration maintained reproductive system in stimulated condition and prevented reproductive regression in photorefractory quail, but did not prevent the onset of scotosensitivity.
Abstract: Circadian rhythms in many metabolic functions including neural (transmitters) and hormonal secretion appear to change with physiological condition. It is also reported that seasonal changes in photoperiodism/reproduction and other metabolic conditions may result from a temporal interaction of circadian neural oscillations that change seasonally. To test this hypothesis, the present study was designed to study the effect of temporal synergism of two neural oscillations (serotonin and dopamine) on relative photorefractoriness of Japanese quail.
Serotonin and dopamine precursor drugs (5-HTP, 5-hydroxytryptophan and L-DOPA, L-dihydroxyphenylalanine) were administered (intraperitonially 5 mg/100 g body weight) at six different time intervals of 0, 4, 8, 12, 16 and 20 hr in sexually mature quail (>12 weeks old). The birds of control group received two daily injections of normal saline. The treatment was given for 13 days in continuous condition of light and then the quail were shifted to intermediate daylength (LD 13.5:10.5 for experiment 1) and short daylength (LD 8:16 for experiment 2). Six weeks following treatment, birds in intermediate daylength showed regressed cloacal gland and testicular activity except in 12-hr group, which exhibited gonadostimulatory condition. But birds of all the groups in short daylength showed complete regression of cloacal gland after 4 weeks of the treatment. In experiment 3, reproductively quiescent relative photorefractory quail maintained under intermediate daylength (LD 13.5:10.5) received 13 daily injections of 5-HTP and L-DOPA at the interval of 12 hr. At 6 weeks post-treatment, it was observed that unlike cloacal gland of control quail, which remained regressed, that of 12-hr quail showed significant development.
These findings indicate that 12-hr temporal interaction of 5-HTP and L-DOPA administration maintained reproductive system in stimulated condition and prevented reproductive regression in photorefractory quail, but did not prevent the onset of scotosensitivity. It is concluded that the 12-hr temporal relationship of circadian serotonergic and dopaminergic oscillations not only eliminates photorefractoriness but may also re-establish photosensitivity in relative photorefractory quail. These findings suggest the regulatory role of neural oscillations and their temporal interaction in the regulation of neuroendocrine–gonadal axis with special reference to photosensitivity/refractoriness. J. Exp. Zool. 305A:3–12, 2006. © 2005 Wiley-Liss, Inc.
19 citations
TL;DR: The data obtained on their immunological characterizations and their presence in important parasite organs give strong indication that they are critical for the survival of filarial parasite and thus can be good vaccine candidates and/or diagnostic markers for human lymphatic filariasis.
Abstract: Background
Like other helminth proteases, filarial proteases have also been shown to require for parasite survival inside the host and mediate various physiologic processes such as tissue invasion, feeding, embryogenesis and host immune evasion. Many of these proteases have shown potential for vaccines and chemotherapeutic agents against active filarial infections. Setaria cervi is a bovine filarial parasite and serves as a good parasite model for the studies in lymphatic filariasis. Recently, a 175 kDa collagenase and leucine aminopeptidase (LAP) have been purified and characterized from the bovine filarial parasite S. cervi and shown to be potential vaccine candidate and diagnostic marker, respectively for human lymphatic filariasis. However, their tissue localizations and putative roles in the parasite biology have not yet been examined and thus remain unclear. Therefore, the current study attempts to localize and explore the putative roles of these two enzymes in S. cervi.
17 citations
TL;DR: The findings suggest that the temporal phase relation of circadian serotonergic and dopaminergic oscillator varies as a function of reproductive status of the bird, and breeding/non-breeding conditions may be induced experimentally by changing the phase relationof these oscillations.
Abstract: Temporal phase relations of circadian hypothalamic neurotransmitters are reported to regulate seasonal reproduction in some avian species. Present experiments were designed to study circadian variation in the hypothalamic concentration of neurotransmitters (serotonin and dopamine) and the plasma thyroxine level in sexually active (long day) and inactive (short day) Japanese Quail. A significant circadian cycle was noted in the hypothalamic content of both serotonin and dopamine, but with different patterns. In breeding Quail, peak activity of serotonin and dopamine was noted at 10.00 A.M. and 10.00 P.M. respectively i.e. at the interval of 12 hours. However, during sexually quiescent condition, peaks of both neurotransmitters occurred at 2.00 P.M. i.e. having a 0-hour temporal relationship. During the breeding phase, the plasma thyroxine level showed a biphasic pattern with two circadian peaks at 10.00 A.M. and 10.00 P.M. whereas in the non-breeding condition a single peak was observed at 10.00 A...
16 citations
TL;DR: It is concluded that photo-sexual conditions alter hypothalamic vasotocinergic and adrenal activity in Japanese quail and the degree of stimulation of the two systems following osmotic stress is higher under gonado-stimulatory LD conditions.
Abstract: The responses of magnocellular neurons of paraventricular nuclei (PVN) and changes to adrenal activity to water deprivation in Japanese quail maintained under gonado-inhibitory and stimulatory photoperiods were examined. Water deprivation of 4 days resulted in a 12% decrease in body weight of sexually regressed short day (SD, 6L:18D) quail, while the decrease was more (18%) in sexually stimulated long day (LD, 16L:8D) quail. The increase in plasma osmolality following water deprivation was also more (47%) in LD than to SD quail (36%). Under the LD condition, quail had increased numbers, sizes and immunostaining of ir-AVT neurons of PVN compared to SD condition. A significant increase in the number of ir-AVT neurons was observed following 4 days of water deprivation in both SD and LD quail compared to their respective fully hydrated controls. However, the degree of response was more under the LD compared to the SD condition suggesting that gonado-stimulatory long days increase the activity/response of the AVT system. Increased adrenal ascorbic acid content (i.e., activity) was also observed to quail of LD when compared to SD treatment. However, osmotic stress led to adrenal hypertrophy and hyperactivity of quail of both of the photoperiodic regimes. Our findings indicate that not only osmotic stress but also photo-gonadal stimulation upregulates the expression of hypothalamic AVT genes and increases the localization of ir-AVT in many neurons of PVN. The above results support the existence of a parallel adrenal-gonad relationship and increase in adrenal function during osmotic stress, which also leads to simultaneous increase in AVT system. We conclude that photo-sexual conditions alter hypothalamic vasotocinergic and adrenal activity in Japanese quail and the degree of stimulation of the two systems following osmotic stress is higher under gonado-stimulatory LD conditions.
14 citations