Spinal and supraspinal midazolam potentiates antinociceptive effects of isoflurane.

The effects of lumbar intrathecal (i.t.) and intracerebroventricular (i.c.v.) midazolam on nociception during isoflurane anaesthesia were studied in rats using the tail-flick test. Rats received i.t. midazolam 2 and 4 microg or i.c.v. midazolam 4 and 8 microg during 1.1, 1.2 and 1.3% isoflurane or without isoflurane. Neither i.t. nor i.c.v. midazolam alone at doses studied influenced nociceptive responses. 1.1% isoflurane showed a minimum antinociceptive effect which was not influenced by i.t. or i.c.v. midazolam. 1.2 and 1.3% isoflurane produced moderate antinociception which was markedly potentiated by both i.t. and i.c.v. midazolam. The effects of midazolam shown in the present study are different from the reported effects of midazolam on opioid-induced antinociception; where spinally administered midazolam potentiates and supraspinal midazolam inhibits the antinociceptive effects of morphine. The present results suggest that midazolam potentiates isoflurane-induced antinociception at doses where no effect is seen alone.

[1]  J. Salgado,et al.  Midazolam-induced hyperalgesia in rats: modulation via GABA(A) receptors at supraspinal level. , 1999, European journal of pharmacology.

[2]  R. Pearce,et al.  Dual actions of volatile anesthetics on GABA(A) IPSCs: dissociation of blocking and prolonging effects. , 1998, Anesthesiology.

[3]  I. Langmoen,et al.  Effect of isoflurane on release and uptake of gamma-aminobutyric acid from rat cortical synaptosomes. , 1998, British journal of anaesthesia.

[4]  C. Goodchild,et al.  Antinociception by intrathecal midazolam involves endogenous neurotransmitters acting at spinal cord delta opioid receptors. , 1996, British journal of anaesthesia.

[5]  P. Mason,et al.  Antagonism of the Antinocifensive Action of Halothane by Intrathecal Administration of GABA‐A Receptor Antagonists , 1996, Anesthesiology.

[6]  D. J. Campbell,et al.  Do nitrous oxide and halothane influence opioid receptor binding in SH-SY5Y human neuroblastoma cells? , 1995, British journal of anaesthesia.

[7]  H. Hill,et al.  The spinal potentiating effect and the supraspinal inhibitory effect of midazolam on opioid-induced analgesia in rats. , 1995, European journal of pharmacology.

[8]  I. Lorenz,et al.  Mechanisms of the influence of midazolam on morphine antinociception at spinal and supraspinal levels in rats. , 1994, European journal of pharmacology.

[9]  J. Antognini,et al.  Does the Brain Influence Somatic Responses to Noxious Stimuli during Isoflurane Anesthesia? , 1994, Anesthesiology.

[10]  J. Antognini,et al.  Does the brain influence somatic responses to noxious stimuli during isoflurane anesthesia , 1994 .

[11]  I J Rampil,et al.  Anesthetic Potency Is Not Altered after Hypothermic Spinal Cord Transection in Rats , 1994, Anesthesiology.

[12]  A. Forster,et al.  Intrathecal midazolam reduces isoflurane MAC and increases the apnoeic threshold in rats , 1994, Canadian journal of anaesthesia = Journal canadien d'anesthesie.

[13]  J. Antognini,et al.  Exaggerated Anesthetic Requirements in the Preferentially Anesthetized Brain , 1993, Anesthesiology.

[14]  J. Fujimoto,et al.  Dynorphin A(1–17) mediates midazolam antagonism of morphine antinociception in mice , 1993, Pharmacology Biochemistry and Behavior.

[15]  I J Rampil,et al.  Anesthetic Potency (MAC) Is Independent of Forebrain Structures in the Rat , 1993, Anesthesiology.

[16]  Y. Inagaki,et al.  Anesthetic Interaction Between Midazolam and Halothane in Humans , 1993, Anesthesia and analgesia.

[17]  P. Coulthard,et al.  An investigation of the effect of midazolam on the pain experience. , 1992, The British journal of oral & maxillofacial surgery.

[18]  C. Goodchild,et al.  Reversal by naloxone of spinal antinociceptive effects of fentanyl, ketocyclazocine and midazolam. , 1991, European journal of anaesthesiology.

[19]  J. S. McDonald,et al.  Differential effects of intrathecal midazolam on morphine-induced antinociception in the rat: role of spinal opioid receptors. , 1991, Anesthesia and analgesia.

[20]  S. Morley,et al.  Intrathecal midazolam for the treatment of chronic mechanical low back pain: Comparison with epidural steroid , 1990, Pain.

[21]  J. Fujimoto,et al.  Spinal dynorphin A (1–17): Possible mediator of antianalgesic action , 1990, Neuropharmacology.

[22]  K. Shimoji,et al.  Effects of isoflurane on spinal inhibitory potentials. , 1990, Anesthesiology.

[23]  T. Yaksh,et al.  Interaction of midazolam and morphine in the spinal cord of the rat , 1990, Neuropharmacology.

[24]  E. London,et al.  Effects of Nitrous Oxide and Halothane on μ and κ Opioid Receptors in Guinea-pig Brain , 1989 .

[25]  D. Niv,et al.  Analgesic and Hyperalgesic Effects of Midazolam: Dependence on Route of Administration , 1988, Anesthesia and analgesia.

[26]  R. Hall,et al.  The anesthetic efficacy of midazolam in the enflurane-anesthetized dog. , 1987 .

[27]  P. Mantegazza,et al.  MODIFICATION OF THE ANTINOCICEPTIVE EFFECT OF MORPHINE BY CENTRALLY ADMINISTERED DIAZEPAM AND MIDAZOLAM , 1982, British journal of pharmacology.

[28]  E. Brunner,et al.  Inhibition of GABA Metabolism in Rat Brain Synaptosomes by Midazolam (RO‐21–3981) , 1981, Anesthesiology.

[29]  E. Eger,et al.  Anesthetic Potencies and the Unitary Theory of Narcosis , 1981, Anesthesia and analgesia.

[30]  E. Eger,et al.  INDUCTION OF ANESTHESIA WITH MIDAZOLAM DECREASES HALOTHANE MAC IN MAN , 1980 .

[31]  E. Eger,et al.  Induction of anesthesia with midazolam decreases halothane MAC in humans. , 1982, Anesthesiology.