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Alternative to ganglionic blockade with anticholinergic and alpha-2 receptor agents.
- Source :
-
Clinical autonomic research : official journal of the Clinical Autonomic Research Society [Clin Auton Res] 2007 Apr; Vol. 17 (2), pp. 77-84. Date of Electronic Publication: 2006 Dec 11. - Publication Year :
- 2007
-
Abstract
- The ganglionic blocking agent trimethaphan (TMP) is no longer produced. Therefore, a need exists for alternative pharmacological approaches to investigate baroreflex control of the circulation. The aim of the present study was to examine baroreflex-mediated cardiovascular responses during the administration of a muscarinic receptor antagonist (glycopyrrolate; GLY: ) and a selective alpha-2 receptor agonist (dexmedetomidine; DEX: ) and to compare responses to ganglionic blockade with TMP. We hypothesized that combined GLY-: DEX: would inhibit the baroreflex similar to TMP. Ten volunteers participated in two study days and were instrumented with pulse oximeter, nasal cannula, ECG, continuous blood pressure monitoring (Finapres), and I.V. catheter for drug infusions. Each study day consisted of a control condition followed by either combined GLY: -DEX: or TMP on alternating days. A Valsalva maneuver was performed under each condition with every subject and six subjects received bolus phenylephrine (25 mug) during GLY: -DEX: and TMP. Combined GLY: -DEX: increased (P < 0.05) blood pressure (99 +/- 4 mmHg) and heart rate (99 +/- 3 bpm) relative to control condition (BP: 90 +/- 2 mmHg; HR: 64 +/- 3 bpm) and TMP infusion decreased (P < 0.05) blood pressure (79 +/- 3 mmHg) while increasing heart rate (88 +/- 3 bpm). Valsalva maneuver elicited a persistent drop in arterial pressure (no phase IIb recovery) with the absence of a phase IV overshoot during both GLY: -DEX: and TMP conditions. Phenylephrine increased systolic pressure 34 +/- 4 mmHg under GLY: -DEX: and 23 +/- 3 mmHg with TMP (P < 0.05). Heart rate only decreased 1 +/- 2 bpm during GLY: -DEX: and 1 +/- 1 bpm with TMP. Taken together, our results suggest that GLY: -DEX: is a reasonable alternative to TMP for baroreflex inhibition.
- Subjects :
- Adrenergic alpha-Agonists therapeutic use
Adult
Blood Pressure drug effects
Cholinergic Antagonists therapeutic use
Dexmedetomidine therapeutic use
Drug Therapy, Combination
Female
Glycopyrrolate therapeutic use
Health
Humans
Male
Phenylephrine therapeutic use
Receptors, Adrenergic, alpha-2 metabolism
Trimethaphan therapeutic use
Valsalva Maneuver
Adrenergic alpha-2 Receptor Agonists
Adrenergic alpha-Agonists pharmacology
Cholinergic Antagonists pharmacology
Dexmedetomidine pharmacology
Ganglion Cysts drug therapy
Phenylephrine pharmacology
Subjects
Details
- Language :
- English
- ISSN :
- 0959-9851
- Volume :
- 17
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Clinical autonomic research : official journal of the Clinical Autonomic Research Society
- Publication Type :
- Academic Journal
- Accession number :
- 17160588
- Full Text :
- https://doi.org/10.1007/s10286-006-0387-7