The effects of plasma and brain magnesium concentrations on lidocaine-induced seizures in the rat

Young J Kim; Claude McFarlane; David S Warner; Max T Baker; Won W Choi; Franklin Dexter

doi:10.1097/00000539-199612000-00016

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The effects of plasma and brain magnesium concentrations on lidocaine-induced seizures in the rat

Journal article

Peer reviewed

The effects of plasma and brain magnesium concentrations on lidocaine-induced seizures in the rat

Young J Kim, Claude McFarlane, David S Warner, Max T Baker, Won W Choi and Franklin Dexter

Anesthesia and analgesia, Vol.83(6), pp.1223-1228

12/1996

DOI: 10.1097/00000539-199612000-00016

PMID: 8942590

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Abstract

Lidocaine and MgSO4 are often coadministered to patients with pregnancy-induced hypertension. This study examined whether MgSO4 alters the lidocaine-seizure threshold in the rat and, if so, whether systemic MgSO4 administration is as effective as intracerebroventricular MgSO4 infusion. In Experiment 1, rats were administered 50% MgSO4 or 0.9% NaCl intravenously (IV) (20 microL/h) for 5 days. In Experiment 2, rats were administered 0.9% NaCl, 0.8% MgSO4, or 2.0% MgSO4 (10 microL/h) via intracerebroventricular infusion for 24 h. All rats then underwent continuous IV lidocaine infusion until onset of electroencephalographic seizures. In Experiment 1, plasma [Mg2+] was greater in the MgSO4 group (5.1 +/- 1.5 mg/dL vs 1.8 +/- 0.3 mg/dL) but neither the dose of lidocaine required to induce seizures (MgSO4 = 19 +/- 2 mg/kg; saline = 23 +/- 5 mg/kg) nor brain [Mg2+] (MgSO4 = 794 +/- 17 micrograms/g; saline = 788 +/- 33 micrograms/g) were changed. In Experiment 2, intracerebroventricular MgSO4 increased both brain [Mg2+] (2% MgSO4 = 923 +/- 79 micrograms/g; saline = 788 +/- 35 micrograms/g) and the lidocaine seizure dose (2% MgSO4 = 39 +/- 7 mg/kg; saline = 26 +/- 3 mg/kg). Although intracerebroventricular administration of MgSO4 produces an anticonvulsant effect, chronic hypermagnesemia does not alter whole brain [Mg2+] and therefore offers no protection from lidocaine-induced seizures in this model.

Blood Pressure

Seizures - blood

Convulsants - adverse effects

Lidocaine - adverse effects

Magnesium Sulfate - pharmacology

Injections, Intraventricular

Anticonvulsants - administration & dosage

Male

Seizures - metabolism

Anticonvulsants - pharmacology

Seizures - chemically induced

Brain - metabolism

Magnesium Sulfate - administration & dosage

Rats

Random Allocation

Body Temperature

Lidocaine - administration & dosage

Carbon Dioxide - blood

Rats, Sprague-Dawley

Oxygen - blood

Convulsants - administration & dosage

Animals

Electroencephalography - drug effects

Magnesium - analysis

Magnesium Sulfate - blood

Infusions, Intravenous

Magnesium - blood

Hydrogen-Ion Concentration

Details

Title: Subtitle: The effects of plasma and brain magnesium concentrations on lidocaine-induced seizures in the rat
Creators: Young J Kim - Department of Anesthesiology, Yonsei University, Seoul, Korea
Claude McFarlane
David S Warner
Max T Baker
Won W Choi
Franklin Dexter
Resource Type: Journal article
Publication Details: Anesthesia and analgesia, Vol.83(6), pp.1223-1228
Publisher: United States
DOI: 10.1097/00000539-199612000-00016
PMID: 8942590
ISSN: 0003-2999
eISSN: 1526-7598
Grant note: R01 GM 39771 / NIGMS NIH HHS
Language: English
Date published: 12/1996
Academic Unit: Health Management and Policy; Anesthesia
Record Identifier: 9983806396302771

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