No abstract available.
Colon* ; Rats, Sprague-Dawley* ; Rectum*

BACKGROUND: Several studies have demonstrated that the transient administration of oxygen improves cognitive performance. However, the effect of long-term oxygen administration remains unknown. This study investigated the impact of long-term oxygen administration on cognitive enhancement. METHODS: Six week old Sprague-Dawley rats (n = 46) were randomly allocated to one of three groups: the control (Control; n = 15), 30 min/day oxygen administration (Oxy30min; n = 16) and 60 min/day oxygen administration groups (Oxy60min; n = 15). The rats in all three groups were administered air or oxygen for 10 weeks. The Morris water maze test was employed to assess the latency (L & Lt), dwelling time (DT) and the total fraction above the mean dwelling time (FmDT) for cognitive performance. RESULTS: Compared to the control group, the Oxy30min and Oxy60min groups showed no differences in their L and Lt. There was a dose-response trend due to oxygen administration. Compared to the control group, the Oxy60min group had a significantly improved DT (P< 0.05). The FmDT also significantly increased in both of the oxygen administration groups, which also showed a dose-response trend (P<0.05). CONCLUSIONS: The present results suggest that long-term (10 weeks) oxygen administration can dose-dependently enhance cognitive performance.
Animals ; Oxygen* ; Rats* ; Rats, Sprague-Dawley

This study was designed to investigate the effective duration of delay period, and to study what changes were induced in the vasculatures of the prefabricated cutaneous flap. Abdominal skin flaps in six groups were fabricated by the subcutaneous implantation of a skeletonized saphenous pedicle using fourty-eight male Sprague-Dawley rats. Forty flaps were elevated at six weeks after fabrication, based solely on the implanted pedicle. Group 1 was used as the control without delay. A surgical delay was carried out at 24, 48, 72 hours, and 7 days prior to flap elevation in the group 2, 3, 4, and 5, respectively. Eight flaps of the group 6 were elevated without delay at 8 weeks after fabrication. Three days later, the flap viability and the numbers of vessels were analyzed quantitatively, and the flap vasculature was evaluated with microangiograms. Flap viabilities of the group 3(95.3+/-7.04) and 4(98.5+/-2.90) were higher than that of the control(83.4+/-11.17, p<0.05). In microangiographic study, the connection between dilated large vessels via choke vessels is dominant finding during the first 24 hours after delay. Dilatations of preexisting small choke vessels started to be appear at 48 hour after delay, and vascular networks of small vessels were progressively developed over the whole flap at 72 hours after delay. The number of vessel, in the flap itself, was increased after 72 hours of delay(p<0.05), but new vessels around the pedicles were more developed at 48 hours after delay(p<0.05). In conclusion, the delay procedure enhances the viability of the prefabricated flap, and the optimal duration is 48 - 72 hours to obtain maximal survival in rats.
Animals ; Dilatation ; Humans ; Male ; Rats ; Rats, Sprague-Dawley ; Skeleton ; Skin

BACKGROUND: Chronic administration of morphine leads to the development of tolerance. We investigated the effects of intrathecal lamotrigine on the spinal morphine tolerance in rats that are undergoing tail flick tests. METHODS: Sprague-Dawley rats were given intrathecal injections of saline 10 microl, lamotrigine 300 microg, morphine 15 microg or lamotrigine plus morphine combinations for 7 days (lamotrigine was given for days 1-7, days 1-3 or days 5-7). The acute and chronic nociceptive sensitivities were assessed using a tail flick test in which the distal 5 cm of the tail was dipped into warm water before and 30 minutes after the drug injection. With successive injections of morphine on day 8, a cumulative antinociceptive dose-response curve was constructed and the 50% effective dose (ED50) was calculated for each study group. RESULTS: The coinjection group of lamotrigine with morphine blocked the development of tolerance, as was shown by the preservation of morphine antinociception over 7 days and the concomitant decrease in the ED50 values on day 8, as compared with the morphine-alone group. Coinjection of lamotrigine blocked the development of morphine tolerance, as shown by the preservation of morphine antinociception over 7 days and the concomitant decrease in the ED50 values on day 8, as compared with the morphine-alone group. CONCLUSIONS: This study suggests that lamotrigine augments the antinociceptive action of both acute and chronic morphine therapy, and it also attenuates the antinociceptive morphine tolerance in rats.
Animals ; Injections, Spinal ; Morphine ; Rats ; Rats, Sprague-Dawley ; Triazines ; Water

To analyze the developmental changes in soma diameters of digastric motoneurons, wheat-germ agglutinin conjugated horseradish peroxidase (WGA-HRP) was injected into the digastric muscle and visualized the retrogradely HRP-labeled motoneurons through tungstate/tetramethylbenzidine (TMB) and following diaminobenzidine (DAB) reactions. The results obtained from Sprague-Dawley rats at postnatal days 1 (P1), 10 (P10) and 30 (P30) indicated as follows: firstly, soma diameters of digastric motoneurons showed unimodal distribution in all postnatal days examined; secondly, the period of P1 to P10 (period 1) showed about 2 times faster growth rate than that of P10 to P30 (period 2); thirdly, the smallest soma examined in each postnatal day exhibited slower growth rate with that of the largest one (increase ratio in soma diameters from P1 to P30, smallest vs. largest =1.62 : 1.93); Finally, relative growth rates a day showed again that period 1 had faster growth rate than that of period 2. Consequently, developmental changes in soma diameters of digastric motoneurons resulted in very different growth rates between both periods. This implies that the growth of the soma is almost completing within P10 and thereafter growing slowly. The period 1 and 2 are corresponding to sucking and sucking/masticatory period, respectively. Therefore present study providing morphological changes in soma diameters of digastric motoneurons suggests that both periods and their different growth rates of the motoneurons in each period may closely be related with each other.
Animals ; Carisoprodol* ; Horseradish Peroxidase ; Rats* ; Rats, Sprague-Dawley

This study was designed to investigate the effect of the surgical delay in the prefabricated cutaneous flap. Abdominal skin flaps (n=40), 4.5x6.0cm in size, were created by the subcutaneous implantation of a saphenous vascular tissue in the male Sprague-Dawley rats. In the groups 1 and 2, the pedicle was skeletonized. In the groups 3 and 4, perivascular muscle cuff or gracilis fascia was retained, respectively. Six weeks later, each flap was elevated as an island flap and reposed in place. All flaps of the group 2 had a 72-hours of delay period. Five days after the flap repositioning, estimation of flap viability, microangiographies, and histological evaluation of vessel development were performed. The groups 2 and 3 showed higher viability in flap survival. The dilated choke vessels and fully developed vascular network were observed in the flap of the group 2, but not typically seen in the other groups. New vessels around the implanted pedicle were more developed in the group 2. Amount of the vessels in the mid-portion of the flap was significantly increased in the groups 2 and 4. In conclusion, the delay procedure enhanced the viability, and its effect was dependent on the new vessel formation around the implanted pedicle.
Fascia ; Humans ; Male ; Rats, Sprague-Dawley ; Skeleton ; Skin

One, two, six and ten week old Sprague-Dawley rats were exposed to carbon monoxide at 3,700 ppm for 30 minutes, and carboxyhemoglobin was measured immediateley, 5, 30, 60, 90, 120 minutes after the exposure. In each time after the exposure, the means of the carboxyhemoglobin levels were "compared among the week age groups. The regression analysis was done using the natural logarithm. of the carboxyhemoglobin concentration as a dependent variable and the time after the exposure. as an independent vaiable. From the regression equation, the half lives of the carboxyhemoglobin were calculated. The one week old rats showed significantly higher carboxyhemoglobin level than other week age rats in the entire time after the exposure. The corrected carboxyhemoglobin concentration calculated by subtracting the normal carboxyhemoglobin level from the me cured carboxyhemoglobin at each age group, showed no uniform differences.
Animals ; Carbon Monoxide ; Carboxyhemoglobin* ; Humans ; Rats* ; Rats, Sprague-Dawley

In order to study the effects of stereotaxic destruction of distinct epileptogenic focus, the amygdala was destroyed with radiofrequency coagulator. A total of twenty Sprague-Dawley rats were divided into two group : the control group which underwent craniectomy on the biparietal area and was instilled crytal penicillin solution into the right amygdala on the basis of stereotaxic coordinates(n=10), and the amygdalectomy group which was performed selective amygdalectomy with radiofrequency coagulator after confirmation of clinical and electroencephalographic epileptic features after proceeding same methods of control group(n=10). The experimental epileptic models in rats were obtained by selective instillation of crystal penicillin solution into the right amygdala. The effects of amygdalectomy were investigated by observation of the changes in behavior and electroencephalographic recordings. The results were as follows ; 1) A typical behavioral seizure was shown in the control group and epilepticform discharge was prominent in crystal penicillin soultion instilled side, but there was no bilateral synchronous epileptic discharges during ictal stages. 2) In comparision to two groups, the severity and the frequency of behavioral seizure were more decreased in the stereotaxic amygdalectomy group. 3) The amygdalectomy group was shwon a significant decrease in amplitude and frequency of spikes, especially during interictal stages, compared to the control group. From the results of electroencephalographic and behavioral analysis, selective amygdalectomy with radiofrequency coagulator seemed to be an effective method to treat the crystal penicillin soulution induced epileptic rats.
Amygdala ; Animals ; Penicillins ; Rats* ; Rats, Sprague-Dawley ; Seizures

The ultimate goal in nerve repair is to restore sensory and motor function of the injured part. The success or failure of this goal depends upon several variables, with the mechanism of injury being one of the more crucial determining factors. At the time of nerve repair, the damaged neural tissue is resected back to what appears to be an uninjured level. However, it is often difficult to determine this level. This study was designed to compare the degree of intraneural scarring over 3-week period in experimental different injuries. In this study, nerve cut, crush, saw, and avulsion injuries were produced in male Sprague-Dawley rats. The extent of nerve damage was assessed based on histology and intraoperative observations on days 1, 8, and 21 after the post-injury. The result of this study demonstrated that the degree of injury can vary from cutting, sawing, crushing to avulsion as well as vary on period; the first 3 weeks after injury. Therefore, a dynamic pathophysiology is induced by a nerve injury. The most severe injury was caused by nerve avulsion, sawing, crushing and cutting mechanisms of injury in order. The intraoperative observation on the first day does not good predictor of the degree of injury. Especially in case of saw injury, the scope of injury was enlarged in course of time, therefore secondary repair on the nerve would be appropriate, when the progress of fibrosis was completed. The extent of injury in the avulsion group will compromise the final result if a primary neurorrhaphy is peformed. Secondary nerve grafting may be the only way to improve sensory function in these injuries. In contrast, the zone of injury in a cut nerve has a tendency to improve over the first 2 to 3 weeks. This would suggest that when an injured nerve is trimmed back to what appears to be a noninjured zone, or normal nerve, no significant additional injury is being induced.
Cicatrix ; Fibrosis ; Humans ; Male ; Rats, Sprague-Dawley ; Sensation ; Transplants

The ultimate goal in nerve repair is to restore sensory and motor function of the injured part. The success or failure of this goal depends upon several variables, with the mechanism of injury being one of the more crucial determining factors. At the time of nerve repair, the damaged neural tissue is resected back to what appears to be an uninjured level. However, it is often difficult to determine this level. This study was designed to compare the degree of intraneural scarring over 3-week period in experimental different injuries. In this study, nerve cut, crush, saw, and avulsion injuries were produced in male Sprague-Dawley rats. The extent of nerve damage was assessed based on histology and intraoperative observations on days 1, 8, and 21 after the post-injury. The result of this study demonstrated that the degree of injury can vary from cutting, sawing, crushing to avulsion as well as vary on period; the first 3 weeks after injury. Therefore, a dynamic pathophysiology is induced by a nerve injury. The most severe injury was caused by nerve avulsion, sawing, crushing and cutting mechanisms of injury in order. The intraoperative observation on the first day does not good predictor of the degree of injury. Especially in case of saw injury, the scope of injury was enlarged in course of time, therefore secondary repair on the nerve would be appropriate, when the progress of fibrosis was completed. The extent of injury in the avulsion group will compromise the final result if a primary neurorrhaphy is peformed. Secondary nerve grafting may be the only way to improve sensory function in these injuries. In contrast, the zone of injury in a cut nerve has a tendency to improve over the first 2 to 3 weeks. This would suggest that when an injured nerve is trimmed back to what appears to be a noninjured zone, or normal nerve, no significant additional injury is being induced.
Cicatrix ; Fibrosis ; Humans ; Male ; Rats, Sprague-Dawley ; Sensation ; Transplants