title: Reestablishment of the hyperglycemia to the normal levels seems not to be essential to the anxiolytic-like effect induced by insulin.
abstract: Diabetes is a chronic metabolic disease accompanied by several comorbidities, including neuropsychiatric conditions. Since the hyperglycemia appears to be the primary factor involved in diabetic conditions, we examined the effect of insulin treatment in diabetic rats on behavioral responses related to anxiety and aversive memory extinction. For this, normoglycemic (NGL) or streptozotocin-diabetic (DBT) rats were submitted to the elevated T maze (ETM) and the contextual conditioned fear (CCF) tests. Therefore, animals were subjected to the prolonged treatment with insulin (6 IU/day, s.c.) to investigate the effect of the treatment on distinct behaviors. When anxiety-like responses such as the inhibitory avoidance (IA) on the ETM and the time of freezing in the first session of the CCF test were evaluated, our data showed a more pronounced anxiogenic-like behavior in DBT animals when compared to NGL ones. In addition, an increased freezing time was observed in DBT animals exposed to the CCF test (sessions 2 and 3) when compared to the NGL group, suggestive of an impairment in the extinction of aversive memory. Insulin treatment induced an anxiolytic-like effect when IA and freezing time (session 1) was evaluated, but did not alter the impaired extinction of aversive memory (sessions 2 and 3). To better understand the involvement of a rigorous control of glycaemia, we also investigated the effect of a lower dose of insulin (3 IU/day, s.c.), unable to reestablish the hyperglycemia to the normal levels, on the same behavioral parameters. Our data show that independent of the dose of insulin, the same effects were observed when animals were evaluated in the ETM and CCF tests. However, only the highest dose of insulin was able to reduce the hyperglycemia to the normal levels. To conclude, our data suggest that a severe glycemic control by insulin treatment seems to be important, but not essential in improving diabetes-induced anxiety.
authors.affiliation: Department of Pharmacology, Biological Sciences Building, Federal University of Paraná, Avenida Coronel H dos Santos S/N, P.O. Box 19031, Curitiba, PR, 81540-990, Brazil.
authors.forename: Eder
authors.initials: E
authors.lastname: Gambeta
authors.affiliation: Department of Pharmacology, Biological Sciences Building, Federal University of Paraná, Avenida Coronel H dos Santos S/N, P.O. Box 19031, Curitiba, PR, 81540-990, Brazil.
authors.forename: Camila Pasquini
authors.initials: CP
authors.lastname: de Souza
authors.affiliation: Department of Pharmacology, Biological Sciences Building, Federal University of Paraná, Avenida Coronel H dos Santos S/N, P.O. Box 19031, Curitiba, PR, 81540-990, Brazil.
authors.forename: Helen
authors.initials: H
authors.lastname: de Morais
authors.affiliation: Department of Pharmacology, Biological Sciences Building, Federal University of Paraná, Avenida Coronel H dos Santos S/N, P.O. Box 19031, Curitiba, PR, 81540-990, Brazil. janaina.zanoveli@ufpr.br.
authors.forename: Janaina Menezes
authors.initials: JM
authors.lastname: Zanoveli
mesh_terms: D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001007:Anxiety / Q000097:blood / Q000188:drug therapy*; D001362:Avoidance Learning / Q000187:drug effects; D001522:Behavior, Animal / Q000187:drug effects; D003921:Diabetes Mellitus, Experimental / Q000097:blood* / Q000188:drug therapy; D005239:Fear / Q000187:drug effects; D006943:Hyperglycemia / Q000097:blood* / Q000188:drug therapy; D007004:Hypoglycemic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D007328:Insulin / Q000494:pharmacology / Q000627:therapeutic use*; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar
chemical_list: D014151:Anti-Anxiety Agents; D007004:Hypoglycemic Agents; D007328:Insulin
keywords: Anxiety; Aversive memory extinction; Diabetes; Glycemic levels; Insulin