Abstract
ENKEPHALINS are endogenous opioid peptides that are derived from a pre- proenkephalin precursor protein. They are thought to be vital in regulating many physiological functions, including pain perception and analgesia, responses to stress, aggression and dominance. Here we have used a genetic approach to study the role of the mammalian opioid system. We disrupted the preproenkephalin gene using homologous recombination in embryonic stem cells to generate enkephalin-deficient mice. Mutant enk(-/-) animals are healthy, fertile, and care for their offspring, but display significant behavioural abnormalities. Mice with the enk(-/-) genotype are more anxious and males display increased offensive aggressiveness. Mutant animals show marked differences from controls in supraspinal, but not in spinal, responses to painful stimuli. Unexpectedly, enk(-/-) mice exhibit normal stress-induced analgesia. Our results show that enkephalins modulate responses to painful stimuli. Thus, genetic factors may contribute significantly to the experience of pain.
Original language | English (US) |
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Pages (from-to) | 535-538 |
Number of pages | 4 |
Journal | Nature |
Volume | 383 |
Issue number | 6600 |
DOIs | |
State | Published - 1996 |
Externally published | Yes |
ASJC Scopus subject areas
- General