L-NAME, A NITRIC OXIDE SYNTHASE INHIBITOR, AS A POTENTIAL COUNTERMEASURE TO POST-SUSPENSION HYPOTENSION IN RATS
| Autor: | S. Watts, Robin R. Socci, Nerimiah Emmett, Danita Eatman, Mohamed A. Bayorh, Wang M, Myrtle Thierry-Palmer |
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| Rok vydání: | 2001 |
| Předmět: |
Male
medicine.medical_specialty Mean arterial pressure Physiology Blood Pressure Vasodilation Baroreflex Nitric Oxide Nitric oxide Rats Sprague-Dawley Hypotension Orthostatic chemistry.chemical_compound Orthostatic vital signs Heart Rate Internal medicine Heart rate Internal Medicine medicine Animals Humans Enzyme Inhibitors biology business.industry General Medicine Space Flight Rats Nitric oxide synthase NG-Nitroarginine Methyl Ester Endocrinology Blood pressure Hindlimb Suspension chemistry biology.protein Nitric Oxide Synthase business |
| Zdroj: | Clinical and Experimental Hypertension. 23:611-622 |
| ISSN: | 1525-6006 1064-1963 |
| Popis: | A large number of astronauts returning from spaceflight experience orthostatic hypotension. This hypotension may be due to overproduction of vasodilatory mediators, such as nitric oxide (NO) and prostaglandins. To evaluate the role of the NO synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) as a countermeasure against the post-suspension reduction in mean arterial pressure (MAP), we assessed the cardiovascular responses and vascular reactivity to 7-day 30 degrees tail-suspension and a subsequent 6 hr post-suspension period in conscious rats. After a pre-suspension reading, direct MAP and heart rate (HR) were measured daily and every 2 hrs post-suspension. The NO synthase inhibitor L-NAME (20 mg/kg, i.v.), or saline, were administered after the 7th day reading prior to release from suspension and at 2 and 4 hrs post-suspension. At 6 hrs post-suspension, vascular reactivity was assessed. While MAP did not change during the suspension period, it was reduced post-suspension. Heart rate was not significantly altered. L-NAME administration reversed the post-suspension reduction in MAP. In addition, the baroreflex sensitivity for heart rate was modified by L-NAME. Thus, the post-suspension reduction in MAP may be due to overproduction of NO and altered baroreflex activity. |
| Databáze: | OpenAIRE |
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