ABSTRACT
Background: Different species of frogs had been used by many researchers for evaluation of analgesic drugs e.g., Rana pipiens and African claw frog. In our study, we used Rana tigrina, which was never used for evaluation of analgesic activity of drugs. So by doing this project, we judged usefulness of R. tigrina to evaluate analgesic drugs. Methods: Animals used were R. tigrina of either sex weighing 100-150 g. Glass flask with porous platform was used for observation of frog. All groups were treated with 4% NaCl solution S.C. on abdomen). Characteristic parameter i.e., number of eye blinkings (this parameter was observed during the pilot study after 4% NaCl S.C. injection on lower third of frogs abdominal wall) were observed before and after drug administration. Each observation was for 5 mins. Centrally and periphrally acting drugs effect was tested on the number of blinks and buccal oscillations. Results: Centrally acting drug inhibit rise in number of eye blinkings and buccal oscillation significantly. Piroxicam diclofenac sodium and ketoprofen decreased rise in number of blinks; but, it was not significant as compared with control. Conclusion: This animal may be used alternative to existing methods of evaluating analgesics in Indian setup.
ABSTRACT
The most important use of neuromuscular blockers is as adjuvant to general anaesthesia where adequate muscle relaxation can be achieved at lighter plane. They also reduce reflex muscle contraction in the region undergoing surgery and assist maintenance of controlled ventilation during anaesthesia. They are particularly helpful in abdominal and thoracic surgery, intubations and endoscopies, orthopedic manipulation, etc. Thus, the risk of respiratory and cardiovascular depression is minimized, and post anesthetic recovery is shortened. The potency ratio of two commonly used neuromuscular agents depolarizing succinylcholine and non depolarizing pancuronium. Double pith a frog and fasten it to a frog board with ventral side up. The sternum was cut through just above the xiphisternum at its base and a pair of muscle attached to it were dissected out and transferred to a dish containing frog Ringer solution at room temperature. All the drug containing solutions were freshly prepared before the experiments Succinyl choline, Pancuronium (1,10,100mg/ml and 1mg/dl) respectively Acetyl choline (10,100mg/ml and 1mg/dl). Acetylcholine solution in various strength were prepared starting from 0.1% to 0.0001%.NMJ blocker Pancuronium was added to the biophase in addition to selected dose (128mg or 256mg) and the contraction of muscle till the 70-80% of inhibition is produced and the difference from sub maximal contractions. The median ED50 was interpolated from the figure taking 50%of inhibition from Height of contraction in mm. The ‘t’ test was performed to compare the ED50 value were interpolated from the regression line to find out the ED50 of the drug. The median doses (ED50) of both of them were calculated graphically and compared. The mean ED50 value of succinylcholine was found to be 1.59 ± 0.08μg (95% confidential limit was from 1.53 to 1.66μg). The ED50 of pancuronium was found to be 0.52 ± 0.10μg with 95% confidence limit being from 0.44 to 0.60μg. The ED50 value of the two drugs was very significantly different (P < 0.001). The potency ratio of pancuronium to succinylcholine was 0.32.
ABSTRACT
In the subadult Rana tigrina administration of 2 μg luteinizing hormone releasing hormone-acetate/frog six days a week for 4 weeks in April resulted in the formation of medium (in all 8 frogs) and large sized (in 4 out of 8 frogs) yolky oocytes and, concomitant increases in the oviductal mass. The ovarian and oviductal masses showed a 10-fold increase over the control frogs. In untreated frogs the ovaries were transparent and contained first growth phase oocytes only. The oviducts were also infantile. The pituitary sections were stained using antisera raised in rabbit against the β-subunit of human luteinizing hormone and human follicle stimulating hormone. Immunoreactivity, staining intensity, cytoplasmic granulation and, cell, nuclear and cytoplasmic areas of gonadotrophs (B2 cells) increased significantly in luteinizing hormone releasing hormone treated frogs. The above findings suggest that pituitary-ovarian axis in the subadult Rana tigrina is responsive to luteinizing hormone releasing hormone and that long-term treatment with the hormone induces cytomorphological changes in the gonadotrophs which result in the conversion of inactive cells into secretory cells. This is accompanied by precocious vitellogenic growth of oocytes in the subadult frogs.
ABSTRACT
The effect of varying photoperiod regimes (LD: 20,4; 4,20; 6,18; 18,6 and 12,12) on ovarian follicular development was analysed in the frog Rana tigrina maintained at ambient and constant 30° ± l°C for 3 months. The experiments were conducted in early recrudescent and quiescent phases. The frogs were fed guppies ad libitum on alternate day. None of the photoperiod regimes had any effect on the ovaries or the fat bodies, whereas exposure to constant high temperature (regardless of photoperiod) during recrudescent phase induced production of greater number of eggs (~ 18000 vs 13000 in controls) of ovulatory sizes (> 1400 μm) compared to the corresponding controls maintained at ambient temperature. Hence, ovarian mass also increased in these frogs. In the quiescent phase, high temperature merely enhanced growth of previtellogenic oocytes. In both the phases high temperature caused a reduction in the fat bodies over the respective controls, possibly due to increased metabolic activity. The above findings indicate that temperature plays a key role in the regulation of ovarian cycle of Rana tigrina and that the photoperiodic mechanisms may not govern the annual recrudescence of ovaries in the frog. The study also shows that the frog exhibits the phenomenon of "phenotypic plasticity" in its reproductive behaviour by producing significantly greater number of eggs in response to elevated temperature.