Differential effects of opioid receptor subtype antagonists upon fluid intake of sucrose, saccharin and carbohydrate maltose dextrin solutions in rats.
Item
-
Title
-
Differential effects of opioid receptor subtype antagonists upon fluid intake of sucrose, saccharin and carbohydrate maltose dextrin solutions in rats.
-
Identifier
-
AAI9315447
-
identifier
-
9315447
-
Creator
-
Beczkowska, Iwona Wanda.
-
Contributor
-
Adviser: Richard J. Bodnar
-
Date
-
1993
-
Language
-
English
-
Publisher
-
City University of New York.
-
Subject
-
Biology, Neuroscience | Health Sciences, Pharmacology | Psychology, Psychobiology
-
Abstract
-
The general non-specific opioid antagonists appear more potent in inhibiting intake of palatable foods, suggesting that opiate antagonist-induced inhibition of ingestive behavior might be due to its effects upon ingestive hedonics. The aim of this dissertation was to evaluate the role of specific opioid receptor subtypes in modulating cumulative (5 min intervals) intake over 1 h of palatable solutions following central administration of general (naltrexone: 1, 5, 20 and 50 ug) and specific mu (beta-funaltrexamine, B-FNA: 1, 5 and 20 ug), mu{dollar}\sb1{dollar} (naloxonazine: 10, 20 and 50 ug), kappa (nor-binaltorphamine, Nor-BNI: 1, 5 and 20 ug), delta{dollar}\sb2{dollar} (naltrindole: 1, 5 and 20 ug) and delta{dollar}\sb1{dollar} (D-Ala{dollar}\sp2{dollar}, Leu{dollar}\sp5{dollar}, Cys{dollar}\sp6{dollar}-enkephalin, DALCE: 10, 20 and 40 ug) opioid receptor antagonists. Antagonists were examined for their ability to alter intake of the sucrose (10%), which has both palatable and nutritive properties, and saccharin (0.1%) which is palatable but non-nutritive. In addition, intake of carbohydrate maltose dextrin (CMD, 10%) was evaluated to determine whether opioid modulation of palatable intake extends to polysaccharide solutions. Finally, to determine whether any opioid antagonist effects upon sucrose, saccharin and CMD intake are specific to their presumed palatable qualities or due to reductions of fluid intake per se, the effects of general and specific opioid receptor subtype antagonists upon deprivation-induced water were studied. Deprivation-induced water intake was significantly reduced by central administration of naltrexone (65%) and B-FNA (40%), but not by naloxonazine or any of the other antagonists suggesting a mu{dollar}\sb2{dollar} mediation of this form of intake. Sucrose intake was significantly inhibited by naltrexone (65%), B-FNA (35%) and Nor-BNI (55%), suggesting a primary kappa role and secondary mu{dollar}\sb2{dollar} role in this form of intake. Saccharin intake was significantly reduced by naltrexone (61%) and by naltrindole (75-90%), suggesting a delta{dollar}\sb2{dollar} mediation of this form of intake. Thus, nutritional consequences of an ingestate appear to be important determinants of which of the opioid receptor subtypes modulates a given response. CMD intake was significantly inhibited by naltrexone (68%) indicating opioid involvement in polysaccharide intake. B-FNA (46%), but not naloxonazine or any other antagonist reduced CMD intake suggesting mu{dollar}\sb2{dollar} mediation. Regression analysis revealed rank-order potencies (ID{dollar}\sb{lcub}50{rcub}{dollar}) of opioid antagonists. Water intake: Nor-BNI (50 mM) {dollar}>{dollar} naltrexone (90 mM) {dollar}\gg{dollar} B-FNA (110 mM) {dollar}>{dollar} DALCE (180 mM) {dollar}>{dollar} naltrindole (260 mM) {dollar}>{dollar} naloxonazine (280 mM). Sucrose intake: Nor-BNI (20 mM) {dollar}>{dollar} naltrexone (50 mM) {dollar}>{dollar} naltrindole (60 mM) {dollar}>{dollar} DALCE (100 mM) {dollar}>{dollar} naloxonazine (120 mM) {dollar}>{dollar} B-FNA (450 mM). Saccharin intake: naltrindole (30 mM) {dollar}>{dollar} Nor-BNI (40 mM) {dollar}>{dollar} naltrexone (70 mM) {dollar}>{dollar} DALCE (100 mM) {dollar}>{dollar} naloxonazine (280 mM) {dollar}>{dollar} B-FNA (470 mM). CMD intake: naltrexone (30 mM) {dollar}>{dollar} Nor-BNI (40 mM) {dollar}>{dollar} naltrindole (90 mM) {dollar}>{dollar} naloxonazine (160 mM) {dollar}>{dollar} DALCE (290 mM) {dollar}>{dollar} B-FNA (660 mM). Thus the mu{dollar}\sb2{dollar} subtype, alters intake with low potency and to a limited degree, suggesting marginal involvement in modulation of palatable intake.
-
Type
-
dissertation
-
Source
-
PQT Legacy CUNY.xlsx
-
degree
-
Ph.D.
