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Background A rat line developed by selective breeding for high alcohol sensitivity has blunted corticosterone responses to alcohol and stress. In the present study, we determined possible differences in adrenal activation after alcohol and motor performance testing between the alcohol-sensitive alcohol-nontolerant and alcohol-insensitive alcohol-tolerant rats. Methods The animals received ethanol (2 g/kg, intraperitoneally), and 30 min later they were subjected to a motor function test (i.e., normal selection test used in the breeding of the lines); the control animals for both rat lines received no treatment and minimal handling. Blood corticosterone and ACTH levels at the single time point were determined by radioimmunoassay, and adrenal activation was determined by in situ hybridization of the immediate early gene c-fos, nor1, nurr1, and NGFI-B mRNA expression. Results The alcohol nontolerant rats had lower corticosterone but normal ACTH levels after ethanol and motor testing. Adrenal early gene expression of all of the genes studied was strongly induced by the treatment in both rat lines, but the inductions of c-fos, nor1, and nurr1 were significantly lower in the alcohol-sensitive animals. Acute treatment with a high dose of ACTH also induced less adrenal gene expression in the alcohol-sensitive animals. Conclusions The results suggest that the reduced adrenal activation is associated with high alcohol sensitivity in a genetic animal model, which is in agreement with the human findings of alcohol insensitivity during glucocorticoid treatment. [ABSTRACT FROM AUTHOR]

Responses of 241 pulpal and 219 non-pulpal nerve fibers to monopolar electrical stimulation were studied in 12 anesthetized cats. Stimulation was carried out with a clinically used pulp tester (Bofors PT-l®) to the intact crown of mandibular canine tooth and to the surrounding soft tissues not further than 1.5 cm from the tooth. Action potentials from nerve preparations containing either a single or a few functional fibers were recorded. The minimum current strength needed w excite the axon ("threshold current") was determined. The purpose of the study was to investigate how specifically monopolar electrical stimulation of the tooth crown excites the nerves of the dental pulp and to what extent fibers of surrounding tissue are affected. The mean threshold of excitation of the pulpal nerve fibers was 28.3 μA ± 1.4 s.e.m. Of 219 non-pulpal fibers sensitive to mechanical stimulation of the tooth and the surrounding area, only 10 fibers of periodontal origin were caused to discharge due to electrical stimulation applied to the tooth crown. Their mean threshold was 96.0 μA ± 5.2 s.e.m. When the receptive fields of 50 mechanoreceptor units in soft tissue were stimulated electrically, only nine responded to current values less than 125 μA. It seems that pulp nerve fibers respond to very much lower current intensities than non-pulpal fibers, when monopolar electrical stimulation is applied to the tooth crown. The risk of activation of non-pulpal nerves in pulp tests seems to be minimal supposing that reasonable current strength is used.