-transparent.png){kind=logo}
The novel and highly selective, conformationally restricted enkephalin analogue for delta-opioid receptors, [D-Pen2,D-Pen5]enkephalin (DPDPE; Pen = penicillamine), was studied in various in vivo tests for analgesia, tolerance and physical dependence. Intracerebroventricular (i.c.v.) administration of DPDPE caused a dose-dependent, naloxone-reversible antinociception, measured with the heat-irradiant (tail-flick) method. Acute tolerance developed to the antinociceptive effect of DPDPE. DPDPE also caused mild signs of physical dependence (withdrawal hypothermia and body weight loss) after repeated peptide treatment. Severe signs of morphine withdrawal (e.g. withdrawal jumping) on the other hand, could not be reversed by the administration of DPDPE. It is concluded that the activation of central delta-opioid receptors may play a role in controlling pain mechanisms, and that this activation is followed by the rapid development of a tolerance to this action.
G L Kovács, and
N Nyolczas, and
M Kriván, and
K Gulya
December 1994,
Pharmacology, biochemistry, and behavior,
G L Kovács, and
N Nyolczas, and
M Kriván, and
K Gulya
January 1990,
Psychopharmacology,
G L Kovács, and
N Nyolczas, and
M Kriván, and
K Gulya
January 1991,
Life sciences,
G L Kovács, and
N Nyolczas, and
M Kriván, and
K Gulya
February 1992,
Journal of medicinal chemistry,
G L Kovács, and
N Nyolczas, and
M Kriván, and
K Gulya
January 1989,
Life sciences,
G L Kovács, and
N Nyolczas, and
M Kriván, and
K Gulya
January 1996,
Peptides,
G L Kovács, and
N Nyolczas, and
M Kriván, and
K Gulya
January 1993,
European journal of pharmacology,
G L Kovács, and
N Nyolczas, and
M Kriván, and
K Gulya
May 1995,
Neuroscience,
G L Kovács, and
N Nyolczas, and
M Kriván, and
K Gulya
October 1996,
Psychopharmacology,
G L Kovács, and
N Nyolczas, and
M Kriván, and
K Gulya
July 1988,
International journal of peptide and protein research,
