Sites of actions of alpha2 agonists in the brain and periphery

Louis, William J.; Jarrott, Bevyn; Conway, Elizabeth L

doi:10.1016/0002-9149(88)90458-4

Cited by 10 publications

(5 citation statements)

References 14 publications

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“…Despite an increase in sympathetic nerve activity, acute systemic hypoxemia leads to decreased blood pressure due to vasodilation [ 21 ]. In contrast to these findings blood pressure remained stable in our study which can be explained by the use of constant rate infusion of alpha-2-agonists during anesthesia masking/reducing vasodilative effects of hypoxia by their vasoconstrictive properties [ 22 ]. Under hypoxic conditions a depression of the myocardium is observed resulting in a reduction of myocardial performance and cardiac ejection fraction [ 23 , 24 ].…”

Section: Discussioncontrasting

confidence: 62%

Effects of controlled hypoxemia or hypovolemia on global and intestinal oxygenation and perfusion in isoflurane anesthetized horses receiving an alpha-2-agonist infusion

et al. 2017

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BackgroundAim of this prospective experimental study was to assess effects of systemic hypoxemia and hypovolemia on global and gastrointestinal oxygenation and perfusion in anesthetized horses. Therefore, we anesthetized twelve systemically healthy warmblood horses using either xylazine or dexmedetomidine for premedication and midazolam and ketamine for induction. Anesthesia was maintained using isoflurane in oxygen with either xylazine or dexmedetomidine and horses were ventilated to normocapnia. During part A arterial oxygen saturation (SaO2) was reduced by reducing inspiratory oxygen fraction in steps of 5%. In part B hypovolemia was induced by controlled arterial exsanguination via roller pump (rate: 38 ml/kg/h). Mean arterial blood pressure (MAP), heart rate, pulmonary artery pressure, arterial and central venous blood gases and cardiac output were measured, cardiac index (CI) was calculated. Intestinal microperfusion and oxygenation were measured using laser Doppler flowmetry and white-light spectrophotometry. Surface probes were placed via median laparotomy on the stomach, jejunum and colon.ResultsPart A: Reduction in arterial oxygenation resulted in a sigmoid decrease in central venous oxygen partial pressure. At SaO2 < 80% no further decrease in central venous oxygen partial pressure occurred. Intestinal oxygenation remained unchanged until SaO2 of 80% and then decreased. Heart rate and pulmonary artery pressure increased significantly during hypoxemia. Part B: Progressive reduction in circulating blood volume resulted in a linear decrease in MAP and CI. Intestinal perfusion was preserved until blood loss resulted in MAP and CI lower 51 ± 5 mmHg and 40 ± 3 mL/kg/min, respectively, and then decreased rapidly.ConclusionsUnder isoflurane, intestinal tissue oxygenation remained at baseline when arterial oxygenation exceeded 80% and intestinal perfusion remained at baseline when MAP exceeded 51 mmHg and CI exceeded 40 mL/kg/min in this group of horses.Trial registry number33.14-42,502-04-14/1547.

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Section: Discussioncontrasting

confidence: 62%

Effects of controlled hypoxemia or hypovolemia on global and intestinal oxygenation and perfusion in isoflurane anesthetized horses receiving an alpha-2-agonist infusion

et al. 2017

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“…Clonidine has a historical role as an antihypertensive drug due to its central alpha 2 effect 47. The mechanism of action is not completely understood.…”

Section: Clonidinementioning

confidence: 99%

Adjuvants to local anaesthesia in ophthalmic surgery

Adams

2011

British Journal of Ophthalmology

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This article reviews the use of adjuvants to local anaesthesia for ophthalmic regional anaesthesia. Hyaluronidase, bicarbonate, epinephrine, muscle relaxants, opiates and clonidine have all been described singly and in combination for use as an adjuvant to ophthalmic regional anaesthesia. The article focuses on the efficacy of the adjuvants with regard to improving akinesia, analgesia, speed of onset and reducing block failure. A description of the pharmacological action of each adjuvant is given followed by a review of randomised control trials, dosage and notable papers on the subject. There is no effective consensus between anaesthetists or surgeons on the use of adjuvants to local anaesthesia and it so is the purpose of this review to draw attention to the wealth of current data and allow an informed decision on the choices available.

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“…The combination of lofexidine and oral THC showed promising results in alleviating withdrawal and preventing relapse in a human laboratory model (Haney et al, 2008). Lofexidine inhibits noradrenergic activity by stimulating ␣ 2 -adrenergic receptors (Louis, Jarrott, & Conway, 1988). Nevertheless, to date, no pharmacological agent has demonstrated efficacy in randomized clinical trials (Nordstrom & Levin, 2007).…”

Section: Pharmacotherapiesmentioning

confidence: 99%

Cognitive function as an emerging treatment target for marijuana addiction.

Sofuoglu¹,

Sugarman²,

Carroll³

2010

Experimental and Clinical Psychopharmacology

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Cannabis is the most widely used illicit substance in the world and demand for effective treatment is increasing. However, abstinence rates following behavioral therapies have been modest, and there are no effective pharmacotherapies for the treatment of cannabis addiction. We propose a novel research agenda and a potential treatment strategy, based on observations that both acute and chronic exposure to cannabis are associated with dose-related cognitive impairments, most consistently in attention, working memory, verbal learning, and memory functions. These impairments are not completely reversible upon cessation of marijuana use and moreover may interfere with the treatment of marijuana addiction. Therefore, targeting cognitive impairment associated with chronic marijuana use may be a promising novel strategy for the treatment of marijuana addiction. Preclinical studies suggest that medications enhancing the cholinergic transmission may attenuate cannabis-induced cognitive impairments, but these cognitive enhancing medications have not been examined in controlled human studies. Preliminary evidence from individuals addicted to other drugs suggests that computerized cognitive rehabilitation may also have utility to improve cognitive function in marijuana users. Future clinical studies optimally designed to measure cognitive function as well as drug use behavior would be needed to test the efficacy of these treatments for marijuana addiction.

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Sites of actions of alpha2 agonists in the brain and periphery

Cited by 10 publications

References 14 publications

Effects of controlled hypoxemia or hypovolemia on global and intestinal oxygenation and perfusion in isoflurane anesthetized horses receiving an alpha-2-agonist infusion

Effects of controlled hypoxemia or hypovolemia on global and intestinal oxygenation and perfusion in isoflurane anesthetized horses receiving an alpha-2-agonist infusion

Adjuvants to local anaesthesia in ophthalmic surgery

Cognitive function as an emerging treatment target for marijuana addiction.

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