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EFFECTS OF ANXIOLYTICS ON STRESS INDUCED ELECTROLYTE BALANCE IN RATS

Farooq, Reshma (2008) EFFECTS OF ANXIOLYTICS ON STRESS INDUCED ELECTROLYTE BALANCE IN RATS. PhD thesis, University of Karachi, Karachi.

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Abstract

Clinical studies have revealed "life event stresses" to stress events during life " are the predisposing factors to anxiety and hypertension in human and animals. Anxiolytic drugs Like diazepam and buspirone decrease stress-induced anxiety and hypertension in human and animals. A role of serum electrolyte is also often implicated in the pathogenesis of hypertension. Sodium potassium, potassium, calcium, and magnesium supplementation Have been shown to modulate blood pressure regulation. The present study was designed To determine the role of electrolytes in the elicitation to stress-induced anxiety and Hypertgension and in the treatment of anxiety by anxiolytic drugs. Important finding of the present study are: 1. Both single and repeated immobilization stresses increased systolic blood pressure and this was associated with a decrease in serum levels of sodium, potassium, and calcium. Plasma osmolality also decreased, whereas concentration of serum magnesium increased and SBP of rats elevated. 2. Single stress produced behavirol deficits, which did not occur following repeated stress, suggesting adaptation occurred. Adaptation however did not occur in stress-induced changes of electrolytes. The effects of stress on SBP were not completely blocked following exposure to repeated restrain stress. 3. Diazepam is a potent anxiolytic that decreased stress-induced enhancement of hypothalamic pituitary adrenal (HPA) axis. These changes may result in alteration in electrolyte balance, plasma osmolality and SBP in rats as well as in human. The present study concerns the effects of different doses of diazepam (1,2.5, and 5 mg/kg) on serum electrolyte, plasma osmolality and SBP of rats. Anxiolysis related variable are also monitored. Results show that the administration diazepam doses significantly increased the serum concentration of electrolytes and plasma osmolality but decreased the serum level magnesium and SBP. Anxiolysis effect in light-dark activity box was also elevated. These effects were dose dependent. The results are discussed in context of role of inhibitory effect of diazepam on HPA axis to be involved in diazepam-induced changes of serum electrolytes and anxiolysis. 4. Single dose administration of diazepam to stressed rats not only reduces anxiety but it may also reverse the effect of stress on electrolyte balance and SBP. The present study concerns the effect of intraperitonealy administration of diazepam (2.5mg/kg) on serum electrolytes. plasma osmolality and SBP of rats. Results showed that diazepam increased the levels of serum sodium, potassium, and calcium while decreased the concentration of magnesium. It also reduced the SBP of stressed rat significantly. It is concluded that the diazepam reversed the stressed produced changes in serum electrolytes. plasma osmolality and SBP of stressed rats. Changes are discussed in contest with changes in HPA axis. 5. The Present experiment is designed to observe that whether repeated administration of diazepam (2.5mg/kg) for 2 weeks produced tolerance effect on electrolyte balance, plasma osmolality and SBP of stressed rats or not. Behavioral changes like food-intake, water-intake and growth rate of unstressed rats were also noted after 2 weeks. Data showed that repeated administration of diazepam (2.5mg/kg) increased the serum electrolytes and plasma osmolality in stressed animals. While serum magnesium and SBP were decreased. Results also showed that diazepam also increased food-intake. water-intake and growth rate of after 2weeks of administration to unstressed rats. It is concluded that repeated administration diazepam did not produce tolerance effects on electrolyte balance, plasma osmolality and SBP of stressed rats. 6. Buspirone is a potent anxiolytic drug. Previous researches reported that buspirone decreased the neural serotonin transmission and reduce the anxiety. These changes may result in alteration in electrolyte balance, plasma osmolality and systolic blood pressure in rats as well as in human. Present study concerns the effects of different doses of buspironc (0.25, 0.5, and 1mg/kg) on serum electrolyte, plasma osmolality and SBP of rats. Anxiolysis related variable are also monitored. Results show that the administration of buspirone doses (0.25mg/kg and 0.5mg/kg) significantly increased the serum concentration of electrolytes and plasma osmolality but decrease the serum level of magnesium and SBP dose dependently. But at the dose of 1mg/kg buspirone has no effect on concentration of serum electrolytes, and plasma osmolality. Anxiolytic effect in light-dark activity box was also elevated after treatment with 0.25mg/kg and 0.5mg/kg doses in dose dependent manner but decreased significantly after administration of 1mg/kg dose of buspirone. The results concluded that buspirone has inhibitory effect on novelty-induced anxiety and increase the electrolytes, plasma osmolality and SBP. 7. Present study was also designed to observe the effect of single administration of buspirone (0.5mg/kg) to restraint stressed electrolyte balance, plasma osmolality and SBP in rats. Results showed higher values of serum sodium, potassium, calcium and plasma osmolality of test animals than control animals while concentration of magnesium and value of SBP were lesser in buspirone treated rats. Results suggest that buspirone inhibit the stress-induced decrease in serum electrolyte, plasma osmolality and increase in magnesium and SBP of stressed rats. 8. Repeated administration of buspirone (0.5mg/kg) for two weeks also increased the serum electrolyte levels and plasma osmolality but reduced the concentration of magnesium and SBP of stressed rats. 9. Behavioural study reported that repeated administration of buspirone (0.5mg/kg) for 2 weeks increased the amount of food and water significantly. Growth rate of rats was also increased. The Present study suggested that stress-induced changes of electrolytes are not altered when similar stresses repeated daily and adaptation is not produced in stress-induced increase in SBP of rats. Present study also reports that single and repeated (two weeks) administration of diazepam (2.5mg/kg) and buspirone (0.5mg/kg) increased the levels of serum electrolytes and plasma osmolality but decreased the concentration of magnesium and SBP of stressed rats. Tolerance was not produced in anxiolytic effects, behavioral effect and effect on electrolyte balance of diazepam or buspirone if drugs administered repeatedly for 2 weeks. Changes in electrolyte balance, plasma osmolality and SBP of rat pretreated with diazepam and buspirone are explainable in term of HPA axis. Anxiolytic drugs reduced the hyper activity of stressed HPA axis that decreases the secretion and activity of adrenal hormones (adrenal corticoid and catecholamines), which increase the stressed electrolyte balance. and reduced SSP of stressed rats

Item Type:Thesis (PhD)
Uncontrolled Keywords:anxiolytics, electrolyte balance, hypertension, anxiety, diazepam, plasma osmolality, buspirone
Subjects:Physical Sciences (f) > Chemistry(f2) > Biochemistry(f2.1)
ID Code:2688
Deposited By:Mr. Javed Memon
Deposited On:05 Aug 2009 12:14
Last Modified:07 Oct 2009 13:31

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