Abstract
BACKGROUND: The spinal cord is an important site where volatile anesthetics decrease sensation and produce immobility. Beyond this knowledge, our understanding of a site of anesthetic action is limited. Previous evidence suggests that dorsal horn neurons with ascending projections may be more susceptible to depression by general anesthetics than local spinal interneurons. In this study we evaluated the effects of volatile and injectable general anesthetics on lumbar dorsal horn neurons with and without ascending projections. METHODS: Thirty-seven adult male rats underwent laminectomies at C1, for placement of a stimulating electrode, and T13/L1, for extracellular recording from the spinal cord dorsal horn. Neuronal responses to heat were evaluated under two doses of halothane, isoflurane, or propofol anesthesia. RESULTS: Under both halothane and isoflurane anesthesia, increasing the dose from 0.8 to 1.2 minimum alveolar concentration (MAC) had no significant effect on heat-evoked responses in neurons that had ascending projections identified via antidromic stimulation (AD) or those without ascending projections (nAD). Heat responses in AD neurons 1 min after IV administration of 3 and 5 mg/kg of propofol were reduced to 60% ± 18% (mean ± se) and 39% ± 14% of control respectively. Similarly, in nAD neurons responses were reduced to 56% ± 14% and 50% ± 10% of control by 3 and 5 mg/kg propofol respectively. CONCLUSIONS: Our findings suggest, at peri-MAC concentrations, these general anesthetics do not preferentially depress lumbar dorsal horn neurons with ascending projections compared to those with no identifiable ascending projections.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 985-990 |
| Number of pages | 6 |
| Journal | Anesthesia and Analgesia |
| Volume | 106 |
| Issue number | 3 |
| DOIs | |
| State | Published - Mar 2008 |
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ASJC Scopus subject areas
- Anesthesiology and Pain Medicine
Cite this
Immobilizing doses of halothane, isoflurane or propofol, do not preferentially depress noxious heat-evoked responses of rat lumbar dorsal horn neurons with ascending projections. / Barter, Linda S; Mark, Laurie O.; Jinks, Steven L.; Carstens, Earl; Antognini, Joseph F.
In: Anesthesia and Analgesia, Vol. 106, No. 3, 03.2008, p. 985-990.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Immobilizing doses of halothane, isoflurane or propofol, do not preferentially depress noxious heat-evoked responses of rat lumbar dorsal horn neurons with ascending projections
AU - Barter, Linda S
AU - Mark, Laurie O.
AU - Jinks, Steven L.
AU - Carstens, Earl
AU - Antognini, Joseph F.
PY - 2008/3
Y1 - 2008/3
N2 - BACKGROUND: The spinal cord is an important site where volatile anesthetics decrease sensation and produce immobility. Beyond this knowledge, our understanding of a site of anesthetic action is limited. Previous evidence suggests that dorsal horn neurons with ascending projections may be more susceptible to depression by general anesthetics than local spinal interneurons. In this study we evaluated the effects of volatile and injectable general anesthetics on lumbar dorsal horn neurons with and without ascending projections. METHODS: Thirty-seven adult male rats underwent laminectomies at C1, for placement of a stimulating electrode, and T13/L1, for extracellular recording from the spinal cord dorsal horn. Neuronal responses to heat were evaluated under two doses of halothane, isoflurane, or propofol anesthesia. RESULTS: Under both halothane and isoflurane anesthesia, increasing the dose from 0.8 to 1.2 minimum alveolar concentration (MAC) had no significant effect on heat-evoked responses in neurons that had ascending projections identified via antidromic stimulation (AD) or those without ascending projections (nAD). Heat responses in AD neurons 1 min after IV administration of 3 and 5 mg/kg of propofol were reduced to 60% ± 18% (mean ± se) and 39% ± 14% of control respectively. Similarly, in nAD neurons responses were reduced to 56% ± 14% and 50% ± 10% of control by 3 and 5 mg/kg propofol respectively. CONCLUSIONS: Our findings suggest, at peri-MAC concentrations, these general anesthetics do not preferentially depress lumbar dorsal horn neurons with ascending projections compared to those with no identifiable ascending projections.
AB - BACKGROUND: The spinal cord is an important site where volatile anesthetics decrease sensation and produce immobility. Beyond this knowledge, our understanding of a site of anesthetic action is limited. Previous evidence suggests that dorsal horn neurons with ascending projections may be more susceptible to depression by general anesthetics than local spinal interneurons. In this study we evaluated the effects of volatile and injectable general anesthetics on lumbar dorsal horn neurons with and without ascending projections. METHODS: Thirty-seven adult male rats underwent laminectomies at C1, for placement of a stimulating electrode, and T13/L1, for extracellular recording from the spinal cord dorsal horn. Neuronal responses to heat were evaluated under two doses of halothane, isoflurane, or propofol anesthesia. RESULTS: Under both halothane and isoflurane anesthesia, increasing the dose from 0.8 to 1.2 minimum alveolar concentration (MAC) had no significant effect on heat-evoked responses in neurons that had ascending projections identified via antidromic stimulation (AD) or those without ascending projections (nAD). Heat responses in AD neurons 1 min after IV administration of 3 and 5 mg/kg of propofol were reduced to 60% ± 18% (mean ± se) and 39% ± 14% of control respectively. Similarly, in nAD neurons responses were reduced to 56% ± 14% and 50% ± 10% of control by 3 and 5 mg/kg propofol respectively. CONCLUSIONS: Our findings suggest, at peri-MAC concentrations, these general anesthetics do not preferentially depress lumbar dorsal horn neurons with ascending projections compared to those with no identifiable ascending projections.
UR - http://www.scopus.com/inward/record.url?scp=39749183489&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=39749183489&partnerID=8YFLogxK
U2 - 10.1213/ane.0b013e318163f8f3
DO - 10.1213/ane.0b013e318163f8f3
M3 - Article
C2 - 18292450
AN - SCOPUS:39749183489
VL - 106
SP - 985
EP - 990
JO - Anesthesia and Analgesia
JF - Anesthesia and Analgesia
SN - 0003-2999
IS - 3
ER -