Pressor responses in morphine-dependent normotensive and freely moving rats

Pressor responses in morphine-dependent normotensive and freely moving rats

502 Pharmacological Research. Vol . 22. Supplement 2. 1990 PRESSOR RESPONSES IN MORPHINE-DEPENDENT NORMOTENSIVE AND FREELY MOVING RATS. S. Vitaglian...

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502

Pharmacological Research. Vol . 22. Supplement 2. 1990

PRESSOR RESPONSES IN MORPHINE-DEPENDENT NORMOTENSIVE AND FREELY MOVING RATS. S. Vitagliano, M. Marmo, V. Susanna, C. Losasso, M. Marovolo, M. Angrisani, A. Rimolo, M. Mangrella - Inst. of Pharmacology and Toxicology (Head: Prof. E. Marmo) 1st Fac. of Medicine and Surgery - University of Naples A variety of studies have helped to establish the central involvement of several neurotransmissions (opiate, GABAerg ic, glutamergic, catecholaminergic type, etc.) in morphine-dependent animals. In normotensive freely moving rats (NOS strain, 250-280 g) rendered or not morphine-dependent (1 mg/g pellets/10 days) according Yamaura et al. (1) the pressor responses to various agents adminestered intracerebroventricularly (icv; 3rd ventricle in 5 sec): L-glutamic acid (G, 0.1 to 10 mcg/an.), NMDA (0.1 to 10 meg/an.), GABA (20 to 80 meg/an.) and clonidine (C, 1 to 5 meg/an.) have been evaluated. Moreover also the catecholamine (A, NA and DA) and arginine-vasopressin (AVP) plasma levels have been evaluated. The induction of morphine-dependence in respect to controls significantly altered (p < 0.05) the pressor responses; in particular it increased the G and NMDA pressor responses and decreased tha GABA and C hypotensive effects. Our data
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2) Marmo E, Rossi F, Lampa E, Berrino L, Russo S, Matera C, Gentile B. Curr Ther Res 1984; 36: 1145-51. This research was supported by MURST and CNR, Rome (Italy).

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© 1990The Italian Pharmacological Society