Abstract
Morphine is known to produce mydriasis in mice. We have found that enkephalins caused a similar effect. Morphine was twice as active as D-Ala-D-Leu-enkephalin (BW-180C), 5 times as active as Met-enkephalin and 7 times as active as Leu-enkephalin. The time course of the effect was shortest for the enkephalins (t1/2 = 8–12 min), intermediate for BW-180C (60 min) and longest for morphine (80 min). Naloxone antagonised the effect of all agents to a similar extent. The question whether enkephalins are involved in the physiological regulation of pupillary diameter was investigated by administering either naloxone or D-phenylalanine to mice. None of these agents changed pupillary size, thus making such an involvement unlikely.
Original language | English |
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Pages (from-to) | 285-287 |
Number of pages | 3 |
Journal | European Journal of Pharmacology |
Volume | 65 |
Issue number | 2-3 |
DOIs | |
State | Published - 1980 |
Keywords
- D-Phenylalanine
- Enkephalins
- Morphine
- Mydriasis
- Naloxone
- Opiate receptors