David P. Clough

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1 The purpose of this study was to investigate whether the separation between the hypotensive and sedative effects of a new series of centrally acting antihypertensive drugs was due to differences between the relative pre-junctional (alpha(2)) and post-junctional (alpha(1)) adrenoceptor agonist properties of the compounds.2 In anaesthetized rats the(More)
Angiotensin is known to facilitate the activity of the sympathetic nervous system, and the purpose of the present study was to investigate the possibility that angiotensin converting enzymes (ACE) inhibitors may interfere with neurogenic vasoconstriction by interfering with this interaction between angiotensin and the nervous system. In a pithed rat(More)
The effects of captopril and angiotensin II on adrenergic neurotransmission have been studied in spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY). In a pithed rat preparation, vasoconstrictor responses evoked by spinal stimulation were greater in SHR than WKY (p less than 0.01). Captopril reduced responses to electrical stimulation and this(More)
The present experiments investigate whether the absence of tachycardia during lowering of blood pressure (BP) with an angiotensin-converting enzyme inhibitor (CEI) in salt-depleted dogs is due to an alteration in the activity of the baroreflex. Baroreflex activity was measured after pharmacological manipulation of BP using intravenous nitroglycerin or(More)
1. Lower-body subatmospheric (negative) pressure led to a prompt reduction in central venous pressure and arterial blood pressure. Arterial blood pressure was then restored within 30 s and there was a tachycardia. These reflex responses have been used to investigate the role angiotensin plays in blood pressure control. 2. The initial plasma renin activity(More)
Cardiovascular status in artificially respired whole animal preparations is dependent, among other factors, upon the maintenance of normal blood gas and acid-base equilibria. A method is described for respiring the pithed rat preparation with oxygen-enriched air. Using this system, ventilation-body weight relations have been defined for maintenance of(More)
1. Lower-body negative pressure (LBNP) was used to stimulate sympathetic reflexes in anaesthetized cats. At -50 mmHg for 10 min it caused transient reduction in central venous pressure and systemic arterial blood pressure. Arterial blood pressure was then restored within 30 s and there was a tachycardia. Central venous pressure showed only partial recovery.(More)