A spinal site mediates opiate analgesia in frogs

Craig Stevens, Paul D. Pezalla

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

The application of acetic acid to the hind leg of a frog will induce a spinally mediated wiping reflex only if the acetic acid concentration is above a certain threshold. By using this reflex as the basis of a test for nociception, we show that morphine sulfate is a potent analgesic in the frog when injected into the lumbar area of the spinal cord. Significant analgesia is induced within 5 min after injection of as little as 0.0316 μg of morphine sulfate. Low doses of morphine sulfate (0.0316 or 0.1 μg) induce analgesia which dissipates within 1 h while for higher doses (0.316, 1.0 or 3.16 μg) the analgesia persists for at least 3 h. The analgesic effect of 0.316 μg of morphine sulfate is completely blocked by naloxone HCl at either 0.158 or 0.316 μg. Animals receiving naloxone alone (0.316 μg) appear to be slightly hyperalgesic compared to saline injected controls but this effect is not significant.

Original languageEnglish
Pages (from-to)2097-2103
Number of pages7
JournalLife Sciences
Volume33
Issue number21
DOIs
StatePublished - 21 Nov 1983

Fingerprint

Opiate Alkaloids
Anura
Analgesia
Morphine
Naloxone
Acetic Acid
Reflex
Analgesics
Pain Measurement
Leg
Spinal Cord
Animals
Injections

Cite this

Stevens, Craig ; Pezalla, Paul D. / A spinal site mediates opiate analgesia in frogs. In: Life Sciences. 1983 ; Vol. 33, No. 21. pp. 2097-2103.
@article{a7552fa6644a43178fe5dff5294cc361,
title = "A spinal site mediates opiate analgesia in frogs",
abstract = "The application of acetic acid to the hind leg of a frog will induce a spinally mediated wiping reflex only if the acetic acid concentration is above a certain threshold. By using this reflex as the basis of a test for nociception, we show that morphine sulfate is a potent analgesic in the frog when injected into the lumbar area of the spinal cord. Significant analgesia is induced within 5 min after injection of as little as 0.0316 μg of morphine sulfate. Low doses of morphine sulfate (0.0316 or 0.1 μg) induce analgesia which dissipates within 1 h while for higher doses (0.316, 1.0 or 3.16 μg) the analgesia persists for at least 3 h. The analgesic effect of 0.316 μg of morphine sulfate is completely blocked by naloxone HCl at either 0.158 or 0.316 μg. Animals receiving naloxone alone (0.316 μg) appear to be slightly hyperalgesic compared to saline injected controls but this effect is not significant.",
author = "Craig Stevens and Pezalla, {Paul D.}",
year = "1983",
month = "11",
day = "21",
doi = "10.1016/0024-3205(83)90333-8",
language = "English",
volume = "33",
pages = "2097--2103",
journal = "Life Sciences",
issn = "0024-3205",
publisher = "Elsevier Inc.",
number = "21",

}

A spinal site mediates opiate analgesia in frogs. / Stevens, Craig; Pezalla, Paul D.

In: Life Sciences, Vol. 33, No. 21, 21.11.1983, p. 2097-2103.

Research output: Contribution to journalArticle

TY - JOUR

T1 - A spinal site mediates opiate analgesia in frogs

AU - Stevens, Craig

AU - Pezalla, Paul D.

PY - 1983/11/21

Y1 - 1983/11/21

N2 - The application of acetic acid to the hind leg of a frog will induce a spinally mediated wiping reflex only if the acetic acid concentration is above a certain threshold. By using this reflex as the basis of a test for nociception, we show that morphine sulfate is a potent analgesic in the frog when injected into the lumbar area of the spinal cord. Significant analgesia is induced within 5 min after injection of as little as 0.0316 μg of morphine sulfate. Low doses of morphine sulfate (0.0316 or 0.1 μg) induce analgesia which dissipates within 1 h while for higher doses (0.316, 1.0 or 3.16 μg) the analgesia persists for at least 3 h. The analgesic effect of 0.316 μg of morphine sulfate is completely blocked by naloxone HCl at either 0.158 or 0.316 μg. Animals receiving naloxone alone (0.316 μg) appear to be slightly hyperalgesic compared to saline injected controls but this effect is not significant.

AB - The application of acetic acid to the hind leg of a frog will induce a spinally mediated wiping reflex only if the acetic acid concentration is above a certain threshold. By using this reflex as the basis of a test for nociception, we show that morphine sulfate is a potent analgesic in the frog when injected into the lumbar area of the spinal cord. Significant analgesia is induced within 5 min after injection of as little as 0.0316 μg of morphine sulfate. Low doses of morphine sulfate (0.0316 or 0.1 μg) induce analgesia which dissipates within 1 h while for higher doses (0.316, 1.0 or 3.16 μg) the analgesia persists for at least 3 h. The analgesic effect of 0.316 μg of morphine sulfate is completely blocked by naloxone HCl at either 0.158 or 0.316 μg. Animals receiving naloxone alone (0.316 μg) appear to be slightly hyperalgesic compared to saline injected controls but this effect is not significant.

UR - http://www.scopus.com/inward/record.url?scp=0021086527&partnerID=8YFLogxK

U2 - 10.1016/0024-3205(83)90333-8

DO - 10.1016/0024-3205(83)90333-8

M3 - Article

C2 - 6606100

AN - SCOPUS:0021086527

VL - 33

SP - 2097

EP - 2103

JO - Life Sciences

JF - Life Sciences

SN - 0024-3205

IS - 21

ER -