Spinal cord distribution of sup 3 H-morphine after intrathecal administration: Relationship to analgesia

Journal Article · Fri Sep 01 00:00:00 EDT 1989 · Anesthesia and Analgesia (Cleveland) (Current Researches); (USA)

OSTI ID:5364365

Nishio, Y; Sinatra, R S; Kitahata, L M; Collins, J G ^[1]

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1. Yale Univ. School of Medicine, CT (USA)

The distribution of intrathecally administered {sup 3}H-morphine was examined by light microscopic autoradiography in rat spinal cord and temporal changes in silver grain localization were compared with results obtained from simultaneous measurements of analgesia. After tissue processing, radio-activity was found to have penetrated in superficial as well as in deeper layers (Rexed lamina V, VII, and X) of rat spinal cord within minutes after application. Silver grain density reached maximal values at 30 min in every region of cord studied. Radioactivity decreased rapidly between 30 min and 2 hr and then more slowly over the next 24 hr. In rats tested for responses to a thermal stimulus (tail flick test), intrathecal administration of morphine (5 and 15 micrograms) resulted in significant dose dependent analgesia that peaked at 30 min and lasted up to 5 hr (P less than 0.5). There was a close relationship between analgesia and spinal cord silver grain density during the first 4 hr of the study. It is postulated that the onset of spinal morphine analgesia depends on appearance of molecules at sites of action followed by the activation of anti-nociceptive mechanisms.

• OSTI ID: 5364365
• Journal Information: Anesthesia and Analgesia (Cleveland) (Current Researches); (USA), Vol. 69:3; ISSN 0003-2999
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
MORPHINE
TISSUE DISTRIBUTION
ANALGESICS
AUTORADIOGRAPHY
DOSE-RESPONSE RELATIONSHIPS
RATS
SPINAL CORD
TRITIUM COMPOUNDS
ALKALOIDS
ANIMALS
CENTRAL NERVOUS SYSTEM
CENTRAL NERVOUS SYSTEM DEPRESSANTS
DISTRIBUTION
DRUGS
HYDROGEN COMPOUNDS
MAMMALS
NARCOTICS
NERVOUS SYSTEM
OPIUM
ORGANIC COMPOUNDS
RODENTS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques