Effect of reserpine and colchicine on neuropeptide mRNA levels in the rat hypothalamic paraventricular nucleus.
Using in situ hybridization and immunohistochemistry, we have studied mRNA and peptide levels in the hypothalamic paraventricular nucleus (PVN) 24 h after a single large dose of reserpine (10 mg/kg, i.p.) and 24 h after an intraventricular (i.c.v.) injection of colchicine (120 microliters/20 microliters saline). Sections of the PVN were hybridized using synthetic oligonucleotide probes complementary to mRNA for corticotropin-releasing hormone (CRH), neurotensin (NT), enkephalin (ENK), vasoactive intestinal polypeptide (VIP) and thyrotropin-releasing hormone (TRH). For immunohistochemistry rabbit antisera to CRH, NT, ENK, VIP and TRH were used. In situ hybridization showed a clear increase in CRH mRNA as compared to control rats after both treatments. Also NT and VIP mRNA could be seen in parvocellular neurons in reserpine and in colchicine-treated rats, whereas we so far have not been able to demonstrate these mRNAs in untreated rats. No changes in TRH mRNA could be detected after reserpine of colchicine. These results provide final evidence that subpopulations of parvocellular PVN neurons can synthesize not only CRH and ENK, but also NT and VIP, in agreement with earlier immunohistochemical results. With immunochemistry, after reserpine, many CRH-, but no NT- or VIP- positive neurons could be observed in the parvoecellular part of the PVN. The present results demonstrate that treatment with two drugs, the monoamine depleting drug reserpine and the mitosis inhibitor colchicine, causes increased levels of mRNA for several peptides in neurons of the PVN, located almost exclusively in its parvocellular part and being part of the hypothalamo-pituitary adrenal axis.
Ceccatelli
S
S
Department of Histology and Neurobiology, Karolinska Institutet, Stockholm.
Cortés
R
R
Hökfelt
T
T
D000818:Animals; D002395:Catecholamines / Q000502:physiology; D003078:Colchicine / Q000494:pharmacology*; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects; D008297:Male; D009479:Neuropeptides / Q000096:biosynthesis* / Q000235:genetics; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects* / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger / Q000096:biosynthesis*; D051381:Rats; D011919:Rats, Inbred Strains; D012110:Reserpine / Q000494:pharmacology*; D013268:Stimulation, Chemical; D013312:Stress, Physiological / Q000503:physiopathology
D002395:Catecholamines; D009479:Neuropeptides; D011518:Proto-Oncogene Proteins; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D012110:Reserpine; D003346:Corticotropin-Releasing Hormone; D003078:Colchicine