Enhanced neuronal expression of calcitonin gene-related peptide in mineralocorticoid-salt hypertension.
Dorsal root ganglia neuronal cell bodies synthesize the vasodilator neuropeptide calcitonin gene-related peptide and innervate the blood vessels and spinal cord sites (laminae I and II) involved in blood pressure regulation. We previously demonstrated that calcitonin gene-related peptide mRNA content is significantly decreased in dorsal root ganglia and that immunoreactive calcitonin gene-related peptide levels are reduced in laminae I and II of the dorsal horn of the spinal cord in the spontaneously hypertensive rat compared with Wistar-Kyoto control rats. To determine whether neuronal calcitonin gene-related peptide expression is also altered in mineralocorticoid-salt hypertension, we quantified calcitonin gene-related peptide mRNA levels in dorsal root ganglia and protein content in laminae I and II of the spinal cord in rats with mineralocorticoid-salt-induced hypertension. To control for pellet implantation, saline drinking water, and/or uninephrectomy, four normotensive groups were similarly studied. By Northern hybridization analysis, the ratio of calcitonin gene-related peptide mRNA to 18S rRNA was increased approximately fivefold in hypertensive rats (33 +/- 7) compared with each of the four normotensive control groups (average of the four groups, 6 +/- 0.5; P < .01, mineralocorticoid-salt group versus each group). The density of the peptide, quantified by computer-assisted image analysis, in laminae I and II in the hypertensive rats was also increased (66 +/- 1 versus average of the four groups, 46 +/- 2 arbitrary units; P < .001, mineralocorticoid-salt group versus each group). In conclusion, neuronal levels of calcitonin gene-related peptide mRNA and protein are increased in mineralocorticoid-salt hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)
Supowit
S C
SC
Department of Internal Medicine, (Division of General Internal Medicine and Hypertension Section), University of Texas Medical Branch, Galveston 77555-1065, USA.
Gururaj
A
A
Ramana
C V
CV
Westlund
K N
KN
DiPette
D J
DJ
D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D006973:Hypertension / Q000378:metabolism*; D007150:Immunohistochemistry; D008297:Male; D008901:Mineralocorticoids; D009474:Neurons / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D012965:Sodium Chloride
D008901:Mineralocorticoids; D012333:RNA, Messenger; D012965:Sodium Chloride; D015740:Calcitonin Gene-Related Peptide