Biomedical subjects

Saida Haider

Publications and source records attributed to Saida Haider.

8 recordsLinked to original sources

PubMed2006

Increased serotonergic functions following adminstration of 1-(1-naphthyl) piperazine in propranolol injected rats.

Propranolol a beta adrenergic antagonist, binds with 5-HT1 receptor. 1-(1-naphthyl) piperazine (1-NP) a derivative of quipazine has serotonin antagonist activity at 5-HT2 and agonist activity at 5-HT1 site. In the present study neurochemical and behavioral effects of 1-NP was monitored in saline and propranolol injected rats. 1NP increased locomotor activity in saline as well as in propranolol injected rats. Administration of propranolol also increased locomotor activity and these increases were more enhanced following 1-NP administration. Levels of 5-HT were not altered following the administration of 1NP in saline as well as propranolol injected rats. 5-HT turnover however decreased by the administration of propranolol Adminstration of 1NP decreased 5-HT turnover in saline but not in propranolol injected rats.

Adrenergic beta-Antagonists↗

PubMed2005

Attenuation of restraint induced behavioral deficits by buspirone and propranolol in rats.

OBJECTIVE: To determine the effect of buspirone and propranolol on restraint stress-induced behavioral deficits in a learned helplessness model. DESIGN: Experimental study. PLACE AND DURATION OF STUDY: The experiment was performed in the Department of Biochemistry, University of Karachi and completed during a period of three months (3 June 2004 to 17 August 2004). SUBJECTS AND METHODS: The study was conducted on 36 male albino Wistar rats. Animals injected with saline, buspirone (0.2 mg/kg) and propranolol (1 mg/kg) for 2 weeks were exposed to an episode of 2 hours restraint stress. Cumulative food intake and body weight changes were monitored over a period of 24 hours. Exploratory activity in the lit area of light dark box was monitored 24 hours after the termination of restraint period. RESULTS: Single (2 hours) restraint stress decreased 24 hours cumulative food intake and growth rate. Exploratory activity in the lit compartment of a light-dark box also decreased. Prior administration of buspirone as well as propranolol attenuated restraint-induced deficits of food intake and growth rate. Administration of buspirone and propranolol increased lit area exploration in unrestrained animals and attenuated restraint-induced deficits of exploration. CONCLUSION: The results show that anorexiogenic and anxiogenic effects of restraint stress were smaller in animals injected with buspirone or propranolol. Buspirone and propranolol could attenuate stress-induced behavioral deficits.

Adrenergic beta-Antagonists↗

PubMed2005

Repeated administration of lead decreases brain 5-HT metabolism and produces memory deficits in rats.

Long-term exposure to low levels of lead (Pb2+) has been shown to produce learning and memory deficits in rodents and humans. These deficits are thought to be associated with altered brain monoamine neurotransmission. Increased brain 5-HT (5-hydroxytryptamine; serotonin) activity is thought to be a prerequisite for maintaining control over the cognitive information process, and is said to have a role in learning and memory. This study was designed to investigate the effects of Pb2+ administration on brain 5-HT metabolism and memory function in rats. Rats were injected daily for three weeks with Pb2+-acetate at a dose of 100 mg/kg body weight. The assessment of memory was done using the Radial arm maze (RAM) and Passive avoidance tests. The results showed spatial working memory (SWM) deficits as well as decreased brain 5-HT metabolism. Increased serotonin activity is considered to be an indication of improved cognitive performance. The results are discussed in the context of lead-induced decreases in 5-HT metabolism playing a role in the impairment of memory.

Animals↗

PubMed2003

Decrease of ethanol intake following repeated injection of serotonin-1A agonist in rats: relationship with receptor responsiveness.

OBJECTIVE: To monitor pre and postsynaptic receptor responsiveness and consumption of ethanol following the repeated administration of a selective serotonin-1A receptor agonist, 8-hydroxy-2-di-n-propylaminotetralin (8-OH-DPAT), to ethanol treated rats. DESIGN: The experimental protocol was designed to administer ethanol orally to rats for three weeks and 8-OH-DPAT during the 3rd week. PLACE AND DURATION OF STUDY: The experiments were performed in the department of Biochemistry, Karachi University. Samples collected after three weeks of treatment were analyzed within a week. SUBJECTS AND METHODS: The study was conducted on 24 males albino Wistar rats treated with ethanol for three weeks. 8-OH-DPAT at a dose of 1mg/kg or saline was injected to ethanol treated rats from day 1 to day 5 during the 3rd week to monitor the effects on ethanol consumption. Pre and postsynaptic responses to 8-OH-DPAT were monitored by injecting the drug on the 6th day to a group of 5-day saline and a group of 5-day 8-OH-DPAT injected animals. Control animals of the two groups were injected with saline. RESULTS: Before the injection of 8-OH-DPAT, weekly intakes of ethanol were highly comparable in the two groups. Administration of 8-OH-DPAT, from day 1 to day 5, decreased ethanol intake. Pre and postsynaptic serotonin-1A receptor dependent responses monitored on the 6th day were higher in 5-day saline than 5-day 8-OH-DPAT injected animals. CONCLUSION: A decrease in the effectiveness of negative feedback control over the synaptic availability of serotonin following 5-day administration of 8-OH-DPAT is involved in the decreases of ethanol consumption.

8-Hydroxy-2-(di-n-propylamino)tetralin↗

PubMed2003

Effects of 2 hrs. restraint stress on brain serotonin metabolism and memory in rats.

Stress is a non-specific response of body to any physiological and psychological demand. Studies on experimental animals show that uncontrollable stress situation produce neurochemical and behavioral deficits In the present study effects of 2 hrs. restraint stress were monitored on brain serotonin metabolism and memory in starved rats. An episode of 2 hrs. restraint stress exhibited a significant decrease in food intake as well as in growth rate in starved rats. The memory function was significantly enhanced following 2 hrs. restraint stress in starved rats. The concentration of Noradrenaline (NA) and Dihydroxyphenyl acetic acid (DOPAC) were increased in the brain while no effect of restraint stress was observed on brain Dopamine (DA) level. Brain levels of 5-hydroxy indoleacetic acid (5-HIAA) was significantly decreased in restraint rats. Tryptophan levels in brain as well as in plasma significantly decreased in starved rats following 2 hrs. restraint stress. The findings are explained in terms of enhanced memory function following restrained stress which may be associated with a decrease in serotonergic function in starved rats.

Journal Article↗

PubMed2002

Serotonin and serotonin 1-A receptors in the failure of ethanol-treated rats to adapt to a repeated stress schedule.

OBJECTIVE: The effects of repeated-restraint stress on brain 5-hydroxytryptamine; serotonin (5-HT) metabolism and functional responses to a selective 5-HT-1A agonist, 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT), are compared in water- and ethanol-treated rats. METHOD: Locally bred male water- or ethanol-treated rats restrained 2 hours per day for 6 days were killed, and whole brains were collected for the neurochemical analysis by high performance liquid chromatography with electrochemical detection (HPLC-EC). In a separate experiment 8-OH-DPAT was injected in water- and ethanol-treated rats to compare elicited hyperactivity syndrome (a postsynaptic response) and effectiveness of the drug in reducing brain 5-HT synthesis (a presynaptic response). RESULTS: A single episode of 2-hour restraint stress decreased 24-hour cumulative food intake in both water- and ethanol-treated rats. Following repeated restraint stress of 2 hours per day for 5 days, the decreases were present in ethanol- but not water-treated rats. The sixth episode of 2-hour restraint stress did not alter brain tryptophan 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) concentrations in water-treated repeatedly restrained rats but decreased tryptophan and increased 5-HT concentration in ethanol-treated rats. Ethanol-treated unrestrained and ethanol-treated repeatedly restrained rats exhibited higher levels of tryptophan 5-HT and 5-HIAA than their respective water-treated controls. Injecting 8-OH-DPAT at a dose of 0.25 mg/kg elicited comparable hyperactivity syndrome in water- and ethanol-treated rats but decreased 5-HT synthesis more in ethanol-treated than in water-treated rats. CONCLUSIONS: The present study shows that ethanol administration for 2 to 3 weeks, although it increases brain 5-HT metabolism, impairs adaptation by increasing the effectiveness of negative feedback control over 5-HT synthesis.

5-Hydroxytryptophan↗

PubMedDate not supplied

Is anorexia in thioacetamide-induced cirrhosis related to an altered brain serotonin concentration?

Anorexia or loss of appetite, one of the most typical symptoms observed in experimental and human cirrhosis, has been proposed to be associated with altered brain serotonin (5-HT) metabolism. In order to evaluate this hypothesis, brain 5-HT, its precursor tryptophan (TRP) and its metabolite 5-hydroxyindole-acetic acid (5-HIAA) were measured in brains of rats with thioacetamide (TAA)-induced liver cirrhosis. Thioacetamide at a dose of 500 mg/l in drinking water was administered for 6 weeks and during this period food intake was carefully measured in order to monitor the loss of appetite or decrease in food intake observed in cirrhosis. Concentrations of brain TRP, 5-HT and 5-HIAA were measured by HPLC with electrochemical detection. In TAA-treated rats, concentrations of 5-HT, TRP and 5-HIAA were increased in brain (44%, 33% and 36% of controls, p < 0.01). In plasma and liver of cirrhotic rats, TRP levels were increased (195% and 43%; p < 0.01). Plasma glucose and albumin levels were decreased (50%; p < 0.01 and 31%). Food intake, growth rate and locomotor activity of TAA-treated rats also decreased (73%, 22% and 73% of controls; p < 0.01). The results of this study show that brain 5-HT concentration in rats is increased in TAA-treated rats and it may, therefore, play an important role in the pathogenesis of anorexia associated with TAA-induced cirrhosis.

Administration, Oral↗

PubMedDate not supplied

Inhibition of restraint-induced neuroendocrine and serotonergic responses by buspirone in rats.

The effects of buspirone (0.5 mg/kg) on the neuroendocrine and serotonergic responses to stress were monitored in rats. Exposure to 2-h of restraint stress increased circulating levels of corticosterone, noradrenaline and glucose. The metabolism of 5-hydroxytryptamine (5-HT; serotonin) increased in the brain. Prior administration of buspirone did not alter levels of corticosterone, noradrenaline and glucose in unrestrained rats, but inhibited stress-induced increase in the activity of hypothalamic-pituitary-adrenal (HPA) axis and circulating levels of glucose. Restraint-induced rise in brain 5-HT and 5-hydroxyindole-acetic acid (5-HIAA) was also attenuated by buspirone. Unrestrained animals injected with buspirone also exhibited a decrease in brain 5-HIAA concentration. The findings are discussed in the context of the role of somatodendritic 5-HT(1A) receptors in responses to stress.

Animals↗