title: Gonadectomy and persistent pain differently affect hippocampal c-Fos expression in male and female rats.
abstract: Hippocampal c-Fos expression was studied in male and female rats after gonadectomy and persistent pain. Three weeks after surgery, animals were sham- or formalin-injected (50 microl, 10%) and placed in a familiar testing apparatus. The formalin-evoked licking, flexing and jerking of the injected paw were recorded for 60 min, c-Fos was determined in the dorsal and ventral hippocampus: dentate gyrus (DG), CA1 and CA3. Gonadectomy induced higher c-Fos in the dorsal DG of both sexes, in all ventral subfields of males and in the ventral CA3 of females. In normal males and females, formalin increased c-Fos in the dorsal DG and in the male ventral subfields. In gonadectomized ones formalin decreased or did not change c-Fos. Gonadectomy induced longer flexing in males and females. These data indicate an important and sex-dependent interaction between gonadal hormones, nociceptive input and neuronal activity in the hippocampus.
authors.affiliation: Institute of Human Physiology, University of Siena, 53100, Siena, Italy. aloisi@unisi.it
authors.forename: A M
authors.initials: AM
authors.lastname: Aloisi
authors.forename: I
authors.initials: I
authors.lastname: Ceccarelli
authors.forename: T
authors.initials: T
authors.lastname: Herdegen
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002369:Castration / Q000009:adverse effects*; D018891:Dentate Gyrus / Q000378:metabolism; D005260:Female; D005557:Formaldehyde / Q000009:adverse effects; D005786:Gene Expression Regulation; D006624:Hippocampus / Q000378:metabolism*; D008297:Male; D010146:Pain / Q000209:etiology / Q000503:physiopathology*; D010147:Pain Measurement; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics*; D051381:Rats; D017208:Rats, Wistar; D012737:Sex Factors
chemical_list: D016760:Proto-Oncogene Proteins c-fos; D005557:Formaldehyde