Septal regulation of male sexual behavior in rats.

Involvement of septal nuclei in modulation of male sexual behavior in rats was investigated. Sexually active Wistar male rats were assigned to intact, sham, lateral septal nuclei lesioned (LSL), and medial septal nuclei lesioned (MSL) groups. All male rats were tested for sexual behavior in an arena in the presence of a sexually receptive female. Intromission and ejaculation latencies were increased, and mount, intromission, and ejaculation frequencies were decreased in the LSL group compared to the intact group. In contrast, mount and intromission latencies were decreased, and pursuit and mount frequencies were increased in the MSL group compared to the intact group. The results indicate that medial septal nuclei may inhibit and lateral septal nuclei may facilitate male sexual behavior in rats.

Effect of short term administration of Tulsi (Ocimum sanctum Linn.) on reproductive behaviour of adult male rats.

Effect of feeding Tulsi leaves along with the normal diet, on the reproductory behaviour of adult male Wistar rats, was studied. Experimental animals were given Tulsi extract in graded doses of 100 mg/kg, 150 mg/kg, 200 mg/kg, and 400 mg/kg along with the normal diet while control group only had similar normal diet. Each dose was given for 15 days and reproductory behaviour monitored in terms of score, on every alternative day. There was significant decrease in sexual behavioural score, when Tulsi leaves extract dose was increased to 200 mg/kg and 400 mg/kg.

Deficits in reproductive behaviour in septally lesioned female rats.

Estrous cycle and sexual behaviour were studied in septally lesioned female albino Wistar rats. In lesioned rats the vaginal smears showed continuous diestrus and the females failed to exhibit sexual receptivity during the postoperative period. Ovarian and uterine weights in lesioned rats were also significantly decreased. The results suggest that the septal nuclei exert a modulatory influence on female sexual behaviour.

Effect of stress on behaviour in rats.

The pattern of activity obtained in rats on a regimen of one hour access to food and water was compared to the activity pattern seen when immobilization stress was added to the same regimen. Food and water were provided at the same time of the day. Immobilization stress decreased the body weight, increased the time taken for grooming, maintaining at the same time the food intake. The water intake also increased significantly but the alcohol intake was variable, 3 of the rats showing an increased intake while the rest showed a decreased intake under this stress regimen. The pattern of activity changed from hyper-activity during food restriction alone to increased activity restricted to the first half of the testing time during added immobilization.

Dissociation of feeding and hoarding after bilateral destruction of lateral septal nuclei in rats.

The interrelationship between Feeding and Hoarding of food pellets was observed to be disrupted following bilateral destruction of lateral septal nuclei in adult male albino rats. The significance of forebrain areas and neuro-endocrinal connection to hypothalamus is discussed.

Autonomic responses to breath holding and its variations following pranayama.

Autonomic responses to breath holding were studied in twenty healthy young men. Breath was held at different phases of respiration and parameters recorded were Breath holding time, heart rate systolic and diastolic blood pressure and galvanic skin resistance (GSR). After taking initial recordings all the subjects practised Nadi-Shodhana Pranayama for a period of 4 weeks. At the end of 4 weeks same parameters were again recorded and the results compared. Baseline heart rate and blood pressure (systolic and diastolic) showed a rendency to decrease and both these autonomic parameters were significantly decreased at breaking point after pranayamic breathing. Although the GSR was recorded in all subjects the observations made were not conclusive. Thus pranayama breathing exercises appear to alter autonomic responses to breath holding probably by increasing vagal tone and decreasing sympathetic discharges.

Role of mid-dorsal caudate nucleus in maintenance of body weight in rats on administration of foods with different caloric densities.

Rats were fed with food of different caloric densities by addition of kaolin or groundnut oil to the normal food powder. The food intake, caloric intake and body weights were noted. These observations were compared before and after bilateral destruction of mid-dorsal caudate nucleus. The food intake before caudatal lesion varied appropriately with the caloric density of food thus maintaining caloric intake and body weight. After mid-dorsal caudatal destruction this feedback mechanism of maintaining body weight was operative with low caloric density diet but not with high caloric diet.

Study of photic versus non-photic cues as entrainers of circadian running activity in rats.

Though relative dominance of photic/non-photic cues on rodent circadian running activity is known, the exclusive role of non-photic entrainers in rats deprived of photic entrainers is not demonstrated and hence present work using retino-hypothalamic pathway blocked male rats (n = 10) was initiated. Blocking is done by enucleation of eyeballs. Circadian running activity is studied before enucleation and after enucleation towards instinctual social cues, food, water and sexual cues provided in activity cage. Twenty four hour activity of rats was recorded kymographically for a fifteen day period before enucleation and for a similar period after enucleation. Analysis of the records revealed that eight animals had predominant diurnal rhythm whereas two animals had predominant nocturnal rhythm. Enucleation of diurnal rats neither altered total running activity pattern nor caused any significant change in the goal compartments thus showing absence of entrainment by photic cues. In contrast nocturnal rats showed gradual shift of activity towards day time on enucleation thus indicating that nocturnal animals were entrained by photic cues. The overriding influence of non-photic entrainers on photic entrainers is discussed.

Sensorimotor changes following lesion of mid-dorsal caudate nucleus in rats.

Effects of mid-dorsal caudate nucleus on sensorimotor changes were studied in rats. After electrolytic lesion of this area of brain there was impairment in sensory functions and decline in motor component was observed to be statistically significant.

Measure of motivational drive for hoarding in laboratory rats.

The drive for hoarding food pellets was studied in adult female rats kept on restricted food schedule, by using varying current strength applied through the metal grid. It was observed that the rats maintained higher hoarding score at proestrus and lowest at diestrus at all strengths of currents used in the experiment indicating stronger drive at proestrus.

Role of ovarian hormones on hoarding in rats--feedback mechanism.

The adult female rats hoard large quantities of food during proestrus and continue hoarding if ovariectomised at proestrus (Group I). The hoarding score is lowest in diestrus and continue to remain low if ovariectomised during this phase (Group II). The scores in Group I and Group II are reversed in intracerebral administration of Progesterone and Estradiol Benzoate respectively into preoptic areas. The significance of the response is discussed on the basis of built-in feedback mechanism for hoarding cyclicity.

Effect of bilateral caudatal lesion on pain threshold in rats.

Pain threshold was determined in eleven adult male rats (Haffkine strain) on electrical stimulation of midpart of tail. Three responses, namely tail withdrawal, vocalization and vocalization afterdischarge were studied. Of these eleven animals, seven in experimental group were subjected to bilateral electrolytic lesion of mid-dorsal caudate nucleus while remaining four animals were sham operated. The increase in pain threshold after caudatal destruction for all the three responses suggests the possible modulatory role of mid-dorsal caudate nucleus in the mechanism of pain.

Role of ovarian hormones in hoarding pattern.

Hoarding pattern studied in 28 adult female albino rats indicated cyclic changes in hoarding corresponding to alterations in estrus cycle. It was observed that the hoarding score was maximum at proestrus and the least at diestrus. Animals ovariectomised at proestrus maintained higher hoarding score and those ovariectomised at diestrus stablised on lower hoarding score. Progesterone administration reduced the score in high-score group and Oestrogen administration improved the score in low score group. Alterations in ovarian hormone levels were thus observed to influence hoarding pattern in rats.

Significance of spatial and temporal dysfunction exhibited by enhanced running activity in hippocampally-lesioned rats.

The present work is designed to study the role of Hippocampus in the control of circadian running activity of rats subject to discrete lesions in ventral hippocampus and having free access to the cues namely food, water, male rat and female rat provided in maze-cum-activity cage indigenously prepared for recording open field behavioral activities. The study was done with 8 male adult albino rats. Those in which lesion was confirmed to be located in antero-ventral hippocampus, exhibited marked increase in running activity with disruption of running activity pattern. There was increase of drive towards socio-sexual cues which were non-rewarding under the present experimental set up. The animals in which lesion was located in posteroventral hippocampal areas showed slight increase in the activity but without disruption of circadian running activity nor was there any significant change in the drive. The functional dissociation observed in present study is believed to be due to involvement of fimbrial/fornical system in the lesion process and therefore responsible for disruption of circadian running activity as well as increase of the running activity in hippocampally-lesioned animals. The present work emphasises the importance of Hippocampus-septum-hippocampus feedback loop in controlling relative time, functioning as internal "stop watch" thus providing a temporal reference and detecting phase relation during activity. Interruption of this loop in hippocampally-lesioned rat probably leads to failure to inhibit inappropriate responses and failure to discriminate rewarding and non-rewarding cues.

Water as entrainer of circadian running activity in rat.

The present work is designed to study the competing influence of periodic presentation of water on the running activity of the rat having free access to the cues fulfilling his instinctual drives, namely, food, water, male rat and primed female. Seven male, adult albino rats were used for the study. The 24 hour activity shift patterns of the incentive drives for food, water, male rat and primed female were recorded with the help of a maze-cum-activity cage with an automatic recording system fabricated in the laboratory, and under different schedules of periodic presentation of water. It was observed that the activity pattern shifted towards the drinking period with burst of running preceding water presentations. The findings of this study show that periodic water presentation is as significant as periodic food presentation in entraining the circadian running activity of the rat.