INDUCTION OF THE C-FOS PROTOONCOGENE IN THE RAT PINEAL-GLAND DURING STRESS

To investigate the effects of stressful stimuli on pineal gland activi ty, male Wistar albino rats (200-250 g, 2-4 per group) were submitted to 30 min of forced immobilization or to unilateral vibrissotomy 30 mi n before sacrifice. In situ hybridization was performed with a S-35-la belled 50-base oligonucleotide probe complementary to nucleolides 270- 319 of rat c-fos on sections containing the pineal gland. Autoradiogra ms were quantified using a JAVA microdensitometer. Stressful stimuli i nduced a significant increase in the expression of c-fos mRNA in the p ineal gland (restraint = 144.3 +/- 14.4 cpm/mm2; hemivibrissotomy = 20 6.7 +/- 29.5 cpm/mm2) as compared to no restraint animals (30.6 +/- 5. 1 cpm/mm2), animals displaying tonic-clonic seizures after an ip (64 m g/kg) injection of pentylenetetrazole (34.0 +/- 4.7 cpm/mm2), or compe tition (70.6 +/- 11.4 cpm/mm2) and RNAase-treated (52.7 +/- 9.1 cpm/mm 2) controls. These results raise the possibility that stressful stimul i may interfere with pineal gland function.