Calcitonin gene-related peptide gene expression in the spontaneously hypertensive rat.
Calcitonin gene-related peptide, a product of the calcitonin gene, is a potent vasodilator neuropeptide. We have demonstrated that dietary calcium deficiency decreased the neuronal (laminae I/II of the dorsal horn of the spinal cord) content of immunoreactive calcitonin gene-related peptide in the normal rat. Neuronal calcitonin gene-related peptide levels are also reduced in the spontaneously hypertensive rat, a model characterized by calcium deficiency. However, the mechanism of this reduction in neuronal calcitonin gene-related peptide could be due to decreased synthesis or increased release. To determine if neuronal calcitonin gene-related peptide messenger RNA (mRNA) levels are also decreased in the spontaneously hypertensive rat, we measured relative calcitonin gene-related peptide mRNA levels (using a genomic hybridization probe specific for alpha- and beta-calcitonin gene-related peptide mRNA) in dorsal root ganglia from spontaneously hypertensive and Wistar-Kyoto control rats. Dorsal root ganglia neuronal cell bodies are a prominent site of calcitonin gene-related peptide synthesis and send axons to peripheral blood vessels and central spinal cord sites (laminae I/II). After normalization of calcitonin gene-related peptide mRNA levels of 18S RNA, the calcitonin gene-related peptide mRNA/18S RNA ratio was significantly decreased approximately threefold in the spontaneously hypertensive rats compared with controls. This alteration in calcitonin gene-related peptide mRNA levels is specific for dorsal root ganglia, because no strain differences in calcitonin gene-related peptide mRNA content were detected in heart or brain.(ABSTRACT TRUNCATED AT 250 WORDS)
Supowit
S C
SC
Department of Internal Medicine, University of Texas Medical Branch, Galveston 77555-0645.
Ramana
C V
CV
Westlund
K N
KN
DiPette
D J
DJ
D000818:Animals; D015152:Blotting, Northern; D015740:Calcitonin Gene-Related Peptide / Q000235:genetics*; D005727:Ganglia, Spinal / Q000378:metabolism; D015870:Gene Expression; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism; D012337:RNA, Ribosomal, 18S / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR / Q000235:genetics*; D011921:Rats, Inbred WKY; D012016:Reference Values
D012333:RNA, Messenger; D012337:RNA, Ribosomal, 18S; D015740:Calcitonin Gene-Related Peptide