Early Ethanol’s Anxiolytic Effects Assessed Through an Unconditional Stimulus Revaluation Procedure

PAUTASSI RM; SANDERS S; MILLER S; SPEAR, N.E.; MOLINA J.C.,

ALCOHOLISM: CLINICAL AND EXPERIMENTAL RESEARCH

Blackwell Publishing

Año: 2006 vol. 30 p. 448 - 459

0145-6008

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0in; margin-bottom:.0001pt; mso-pagination:widow-orphan; mso-layout-grid-align:none; punctuation-wrap:simple; text-autospace:none; font-size:10.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-fareast-language:ES;} p.BodyText21, li.BodyText21, div.BodyText21 {mso-style-name:"Body Text 21"; margin:0in; margin-bottom:.0001pt; text-align:justify; text-indent:35.45pt; line-height:200%; mso-pagination:widow-orphan; mso-layout-grid-align:none; punctuation-wrap:simple; text-autospace:none; font-size:12.0pt; mso-bidi-font-size:10.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-fareast-language:ES;} @page Section1 {size:8.5in 11.0in; margin:1.0in 1.25in 1.0in 1.25in; mso-header-margin:.5in; mso-footer-margin:.5in; mso-paper-source:0;} div.Section1 {page:Section1;} -->    Background: Even though ethanol is considered to exert antianxiety effects, the existence of such properties during early ontogeny of the rat has rarely received attention, mainly due to the restricted behavioral repertoire of the pup. This study evaluated ethanol’s anxiolytic properties in preweanling rats through an unconditional stimulus revaluation procedure.    Methods: Optimal parameters for the acquisition of an odor avoidance response in preweanlings were obtained in Experiment 1. In Experiment 2 pups experienced four conditioning trials defined by a 5 min exposure to a lemon odor while they were intraorally infused with a sapid aversive stimulus (citric acid). 24 hours later, pups were briefly exposed to the acid 5 min after being administered with 0.0, 0.25, 0.5, 1.25 or 2.5 g/kg of ethanol. Odor preferences were then evaluated in a two-way odor preference test. Blood ethanol concentrations (BEC’s) derived from these doses were assessed in Experiment 3. In Experiment 4 citric acid mediated-conditioning was followed by a similar odor-preference test after pups were re-exposed to the acid either 5 or 25 min after receiving a 2,5 g/kg ethanol dose. Ethanol’s effects upon the expression of the avoidance response were also analyzed in an alternative rat strain (Experiment 5).    Results: Moderate to low ethanol doses ameliorated the otherwise strong avoidance response. Further experiments a) Replicated these phenomena b) Established that they are correlated with BEC’s in the range of 17-70 mg% and c) Indicated that ethanol’s influence upon an avoidance response changes as a function of the temporal course of the intoxication.    Conclusions: These findings show the first conclusive evidence of early anxiolytic properties of ethanol and indicate that this drug exerts differential motivational effects during the course of the intoxication. It is suggested that the devaluation procedure should be considered as an alternative method to evaluate motivational properties of ethanol.