Thesis (Ph.D.) -- Virginia Commonwealth University, 2006. / Title from title-page of electronic thesis. Prepared for: School of Nursing. Bibliography: p. 123-136.

Thesis (M.S.)--University of Michigan, 1987.

Thesis (M.S.)--University of Michigan, 1987.

<p>Tulbaghia violacea Harv. (Alliaceae) is a small bulbous herb which belongs to the family, Alliaceae, most commonly associated with onions and garlic. In South Africa (SA), this&nbsp / herb has been traditionally used in the treatment of various ailments, including fever, colds, asthma, paralysis, hypertension (HTN) and stomach problems. The aim of this study&nbsp / was to evaluate the effect of methanol leaf extracts (MLE) of T. violacea on the blood pressure (BP) and heart rate (HR) in anaesthetized male spontaneously hypertensive rats / &nbsp / and to find out the mechanism(s) by which it acts. The MLE of T. violacea (5 - 150 mg/kg), angiotensin I (ang I, 3.1 - 100 &mu / g/kg), captopril (10 mg/kg), angiotensin II (ang II, 3.1 - 50&nbsp / g/kg), losartan (30 mg/kg), phenylephrine (0.01 &ndash / 0.16 mg/kg), prazosin (1 mg/kg), dobutamine (0.2 &ndash / 10.0 &mu / g/kg), propranolol (0.1 - 12.8 mg/kg), muscarine (0.16 -10 &mu / g/kg),&nbsp / and atropine (0.02 - 20.48 mg/kg) were administered intravenously into male spontaneously hypertensive rats (SHR) weighing between 300 g and 350 g and aged less than 5&nbsp / months. The MLE of T. violacea and/or the standard drugs were infused alone, simultaneously, or separately into each animal. The BP and HR were measured via a pressure&nbsp / transducer connecting the femoral artery and the Powerlab. The vehicle (0.2 mls of a mixture of dimethylsulfoxide and normal saline), T. violacea (60 mg/kg) and captopril (10&nbsp / mg/kg) were injected intraperitoneally into some SHR for 21 days to investigate the chronic effect of these agents on plasma levels of aldosterone. The mean change, the mean&nbsp / of the individual percentage changes and the percentage difference (in mean) observed with each intervention was calculated and statistically analyzed using the Student&rsquo / s t test&nbsp / for significant difference (p &lt / 0.05). The Microsoft Excel software was used for statistical analysis. T. violacea significantly (p &lt / 0.05) reduced the systolic, diastolic, and mean&nbsp / arterial BP / and HR dose-dependently. In a dose-dependent manner, ang I, ang II, phenylephrine significantly (p &lt / 0.05) increased the BP, while propranolol, muscarine and&nbsp / atropine reduced the BP. The increases in BP due to dobutamine were not dose-dependent. In a dose dependent manner, phenylephrine and propranolol reduced the HR, while dobutamine increased the HR. The effect of ang I, ang II, muscarine and atropine on HR were not dose-dependent / with both increases as well as decreases observed with ang&nbsp / I, and II and atropine, while decreases were seen with muscarine. Captopril produced&nbsp / significant (p &lt / 0.05) reduction in BP which were not associated with any change in HR. The co-infusion of ang I with the MLE produced significant (p &lt / 0.05) reduction in BP, which were not associated with significant changes in HR. The co-infusion of ang II with the&nbsp / MLE did not produce any significant changes in BP or HR when compared to the infusion of the standard drug alone. The co-infusion of phenylephrine with the MLE did not&nbsp / produce any significant change in BP or HR when compared to the values obtained with the infusion of the standard drug alone, in both the absence and presence of prazosin.&nbsp / The co-infusion of dobutamine with T. violacea produced siginificant (p &lt / 0.05) increases in DBP which were associated with significant (p &lt / 0.05) reductions in HR, when&nbsp / compared to the values obtained with the infusion of the standard drug alone. Theco-infusion of atropine with the MLE did not produce any significant change in BP or HR when&nbsp / compared to the values obtained with the infusion of atropine alone. However, the infusion of T. violacea, 20 minutes after pre-treating animals with atropine (5.12 mg/kg) lead to&nbsp / dose dependent significant (p &lt / 0.05) increases in BP, which were associated with dose-dependent increases in HR. The chronic treatment of animals with T. violacea or&nbsp / captropril produced (a) signicant (p &lt / 0.05) reductions in the plasma levels of aldosterone when compared to the values obtained in the vehicle-treated group, (b) produced&nbsp / signifiant (p &lt / 0.05) reduction in BP in the captopril treated group when compared to the vehicle-treated, (c) did not produce any signficant change in BP in the T. violacea-treated&nbsp / group when compared to the vehicle-treated group and (d) did not produce any signifiant change in HR or body weight in any of the groups. The result obtained in this study&nbsp / suggests that T. violacea reduced BP and HR in the SHR. Secondly, the BP and HR reducing effect of the MLE may involve a) the inhibition of the ACE, b) the inhibition of the &beta / 1&nbsp / adrenoceptors, c) the stimulation of the muscarinic receptors and d) the reduction of the levels of aldosternone in plasma. The results also&nbsp / suggest that the MLE may not act&nbsp / through the angiotensin II receptors or the &alpha / 1 adrenergic receptors.&nbsp / </p>

<p>Tulbaghia violacea Harv. (Alliaceae) is a small bulbous herb which belongs to the family, Alliaceae, most commonly associated with onions and garlic. In South Africa (SA), this&nbsp / herb has been traditionally used in the treatment of various ailments, including fever, colds, asthma, paralysis, hypertension (HTN) and stomach problems. The aim of this study&nbsp / was to evaluate the effect of methanol leaf extracts (MLE) of T. violacea on the blood pressure (BP) and heart rate (HR) in anaesthetized male spontaneously hypertensive rats / &nbsp / and to find out the mechanism(s) by which it acts. The MLE of T. violacea (5 - 150 mg/kg), angiotensin I (ang I, 3.1 - 100 &mu / g/kg), captopril (10 mg/kg), angiotensin II (ang II, 3.1 - 50&nbsp / g/kg), losartan (30 mg/kg), phenylephrine (0.01 &ndash / 0.16 mg/kg), prazosin (1 mg/kg), dobutamine (0.2 &ndash / 10.0 &mu / g/kg), propranolol (0.1 - 12.8 mg/kg), muscarine (0.16 -10 &mu / g/kg),&nbsp / and atropine (0.02 - 20.48 mg/kg) were administered intravenously into male spontaneously hypertensive rats (SHR) weighing between 300 g and 350 g and aged less than 5&nbsp / months. The MLE of T. violacea and/or the standard drugs were infused alone, simultaneously, or separately into each animal. The BP and HR were measured via a pressure&nbsp / transducer connecting the femoral artery and the Powerlab. The vehicle (0.2 mls of a mixture of dimethylsulfoxide and normal saline), T. violacea (60 mg/kg) and captopril (10&nbsp / mg/kg) were injected intraperitoneally into some SHR for 21 days to investigate the chronic effect of these agents on plasma levels of aldosterone. The mean change, the mean&nbsp / of the individual percentage changes and the percentage difference (in mean) observed with each intervention was calculated and statistically analyzed using the Student&rsquo / s t test&nbsp / for significant difference (p &lt / 0.05). The Microsoft Excel software was used for statistical analysis. T. violacea significantly (p &lt / 0.05) reduced the systolic, diastolic, and mean&nbsp / arterial BP / and HR dose-dependently. In a dose-dependent manner, ang I, ang II, phenylephrine significantly (p &lt / 0.05) increased the BP, while propranolol, muscarine and&nbsp / atropine reduced the BP. The increases in BP due to dobutamine were not dose-dependent. In a dose dependent manner, phenylephrine and propranolol reduced the HR, while dobutamine increased the HR. The effect of ang I, ang II, muscarine and atropine on HR were not dose-dependent / with both increases as well as decreases observed with ang&nbsp / I, and II and atropine, while decreases were seen with muscarine. Captopril produced&nbsp / significant (p &lt / 0.05) reduction in BP which were not associated with any change in HR. The co-infusion of ang I with the MLE produced significant (p &lt / 0.05) reduction in BP, which were not associated with significant changes in HR. The co-infusion of ang II with the&nbsp / MLE did not produce any significant changes in BP or HR when compared to the infusion of the standard drug alone. The co-infusion of phenylephrine with the MLE did not&nbsp / produce any significant change in BP or HR when compared to the values obtained with the infusion of the standard drug alone, in both the absence and presence of prazosin.&nbsp / The co-infusion of dobutamine with T. violacea produced siginificant (p &lt / 0.05) increases in DBP which were associated with significant (p &lt / 0.05) reductions in HR, when&nbsp / compared to the values obtained with the infusion of the standard drug alone. Theco-infusion of atropine with the MLE did not produce any significant change in BP or HR when&nbsp / compared to the values obtained with the infusion of atropine alone. However, the infusion of T. violacea, 20 minutes after pre-treating animals with atropine (5.12 mg/kg) lead to&nbsp / dose dependent significant (p &lt / 0.05) increases in BP, which were associated with dose-dependent increases in HR. The chronic treatment of animals with T. violacea or&nbsp / captropril produced (a) signicant (p &lt / 0.05) reductions in the plasma levels of aldosterone when compared to the values obtained in the vehicle-treated group, (b) produced&nbsp / signifiant (p &lt / 0.05) reduction in BP in the captopril treated group when compared to the vehicle-treated, (c) did not produce any signficant change in BP in the T. violacea-treated&nbsp / group when compared to the vehicle-treated group and (d) did not produce any signifiant change in HR or body weight in any of the groups. The result obtained in this study&nbsp / suggests that T. violacea reduced BP and HR in the SHR. Secondly, the BP and HR reducing effect of the MLE may involve a) the inhibition of the ACE, b) the inhibition of the &beta / 1&nbsp / adrenoceptors, c) the stimulation of the muscarinic receptors and d) the reduction of the levels of aldosternone in plasma. The results also&nbsp / suggest that the MLE may not act&nbsp / through the angiotensin II receptors or the &alpha / 1 adrenergic receptors.&nbsp / </p>

Made available in DSpace on 2016-06-02T19:22:56Z (GMT). No. of bitstreams: 1 Retido.pdf: 19733 bytes, checksum: 6aad255badc436a06364517de2344ab6 (MD5) Previous issue date: 2012-04-26 / Universidade Federal de Minas Gerais / The goal of the present study was to determine if nitric oxide (NO) acting on brain of frogs presents an inhibitory tonus on mean arterial blood pressure (MAP) and heart rate (HR) by reducing the sympathetic activity dependent on &#945; and/or &#946; adrenergic receptors during winter and spring/summer seasons. Thus, body temperature and MAP was measured by a telemetry device implanted into the abdominal cavity of American bullfrogs, with the catheter of the device inserted into the left aortic arch for AP and HR measurements. Additionally, blood cell flux was measured using a laser Doppler flowmeter sutured to the pelvic skin to calculate cutaneous vascular condutance (CVC). A guide cannula was implanted into brain lateral ventricle for injections of L-NMMA (non selective NO synthase inhibitor) or mCSF (mock cerebrospinal fluid, vehycle) and a PE cannula was inserted in the femoral vein for bolus injections of adrenergic antagonists, prazosin (&#945;1) and sotalol (&#946;), and agonists, phenylephrine (&#945;1) and isoproterenol (&#946;) or Ringer solution. Animals were maintained at 25 °C during all the experiments. Mean AP, but not HR, was greater during winter than spring/summer. L-NMMA increased MAP, but did not change HR, during both seasons. The pre-treatment with prazosin attenuated and soltalol accentuated the hypertensive effect of LNMMA in both seasons. We conclude that NO seems to act on the brain of frogs as a hypotensive agent via, at least in part, the inhibition of the symphathetic activity dependent on &#945;, and &#946;, adrenergic receptors. / O objetivo do presente trabalho foi determinar se o óxido nítrico (NO) atuando no SNC de rãs apresenta tônus inibitório sobre a pressão arterial média (PAM) e a frequência cardíaca (FC) reduzindo a atividade simpática dependente de receptores a e/ou b adrenérgicos durante o inverno e a primavera/verão. Desta forma, a temperatura corporal e a PAM foram mensuradas por meio de um transmissor de telemetria implantado na cavidade abdominal de rãs-touro, e o cateter do transmissor foi inserido no arco aórtico esquerdo para as medidas de pressão arterial e FC. Adicionalmente, o fluxo de células sanguíneas foi avaliado por meio de um sensor a laser Doppler suturado à pele da região pélvica ventral do animal para as medidas de condutância vascular cutânea (CVC). Uma cânula foi implantada no ventrículo lateral para injeções de L-NMMA (inibidor não seletivo da NOS) ou líquor artificial (veículo) e uma cânula de polietileno PE50 foi inserida na veia femoral para injeções in bolus de antagonistas adrenérgicos, prazosin (&#945;1) e sotalol (&#946;), e agonistas, fenilefrina (&#945;1) e isoproterenol (&#946;) ou solução Ringer. Os animais foram mantidos a 25 °C durante todos os experimentos. A PAM, mas não a FC, foi maior no inverno em relação à primavera/verão. A CVC da região pélvica ventral foi maior no inverno em relação à primavera/verão. O L-NMMA aumentou a PAM e diminuiu a CVC, mas não alterou a FC, durante ambas as estações. O pré-tratamento com prazosin atenuou e o sotalol acentuou o efeito pressor do L-NMMA em ambas as estações. Podemos concluir que o NO parece atuar no encéfalo de rãs como um agente hipotensor via, em parte, inibição da atividade simpática dependente de receptores alfa vasoconstritores e beta adrenérgicos vasodilatadores.