The influence of CRF and alpha-helical CRF(9-41) on rat fear responses, c-Fos and CRF expression, and concentration of amino acids in brain structures.
In the present study we have examined the influence of intracerebroventricullary administered CRF, and a non-selective CRF receptor antagonist, alpha-helical CRF((9-41)), on rat conditioned fear response, serum corticosterone, c-Fos and CRF expression, and concentration of amino acids (in vitro), in several brain structures. Pretreatment of rats with CRF in a dose of 1 microg/rat, enhanced rat-freezing response, and further increased conditioned fear-elevated concentration of serum corticosterone. Moreover, exogenous CRF increased aversive context-induced expression of c-Fos in the parvocellular neurons of the paraventricular hypothalamic nucleus (pPVN), CA1 area of the hippocampus, and M1 area of the frontal cortex. A different pattern of behavioral and biochemical changes was present after pre-test administration of alpha-helical CRF((9-41)) (10 microg/rat): a decrease in rat fear response and serum corticosterone concentration; an attenuation of fear-induced c-Fos expression in the dentate gyrus, CA1, Cg1, Cg2, and M1 areas of the frontal cortex; a complete reversal of the rise in the number of CRF immunoreactive complexes in the M2 cortical area, induced by conditioned fear. Moreover, alpha-helical CRF((9-41)) increased the concentration of GABA in the amygdala of fear-conditioned rats. Altogether, the present data confirm and extend previous data on the integrative role of CRF in the central, anxiety-related, behavioral and biochemical processes. The obtained results underline also the role of frontal cortex and amygdala in mediating the effects of CRF on the conditioned fear response.
Skórzewska
Anna
A
Department of Neurochemistry, Institute of Psychiatry and Neurology, 9 Sobieskiego Street, 02-957 Warsaw, Poland.
Bidziński
Andrzej
A
Hamed
Adam
A
Lehner
Małgorzata
M
Turzyńska
Danuta
D
Sobolewska
Alicja
A
Maciejak
Piotr
P
Szyndler
Janusz
J
Wisłowska-Stanek
Aleksandra
A
Płaźnik
Adam
A
D000465:Algorithms; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D001921:Brain / Q000033:anatomy & histology / Q000187:drug effects* / Q000378:metabolism; D001923:Brain Chemistry / Q000187:drug effects; D003213:Conditioning, Psychological / Q000187:drug effects; D003345:Corticosterone / Q000378:metabolism; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism* / Q000494:pharmacology*; D018846:Excitatory Amino Acids / Q000737:chemistry / Q000378:metabolism*; D005239:Fear / Q000187:drug effects*; D008297:Male; D009994:Osmolar Concentration; D010446:Peptide Fragments / Q000494:pharmacology*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D018846:Excitatory Amino Acids; D010446:Peptide Fragments; D016760:Proto-Oncogene Proteins c-fos; D003346:Corticotropin-Releasing Hormone; C045089:corticotropin releasing hormone (9-41); D003345:Corticosterone