Peptidergic mechanisms of hyperthermia-induced convulsions in early postnatal ontogeny in rat: The role of pituitary adenylate cyclase-activating polypeptide (PACAP) and arginine-vasopressin (AVP)

2000 ◽  
Vol 94 (1-3) ◽  
pp. 52
Author(s):  
Serguei A. Chepurnov ◽  
Alexei A. Ponomarenko ◽  
Nina E. Chepurnova
1986 ◽  
Vol 251 (2) ◽  
pp. F266-F270 ◽  
Author(s):  
J. K. Kim ◽  
S. N. Summer ◽  
A. E. Erickson ◽  
R. W. Schrier

Two groups of Sprague-Dawley rats, Harlan (H) and Charles River (CR), were discovered in that the medullary thick ascending limb (MAL) had a profoundly different adenylate cyclase response to arginine vasopressin (AVP). Using these two groups of rats, we studied the correlation between AVP action on the MAL and maximal urinary concentration. AVP (10(-6) M) significantly stimulated adenylate cyclase in MAL of H rats (7.4 +/- 0.9 to 43.8 +/- 4.6 fmol cAMP formed X 30 min-1 X mm-1, P less than 0.001) but not in CR rats (10.3 +/- 1.4 to 12.7 +/- 2.0 fmol cAMP formed X 30 min-1 X mm-1, NS). In contrast, AVP significantly stimulated adenylate cyclase of cortical, outer and inner medullary collecting tubules from both H and CR rats. Glucagon (10(-6) M) significantly stimulated adenylate cyclase of MAL from both H and CR rats. After 48 h of fluid deprivation, urinary osmolality was significantly higher (P less than 0.001) in the H (4,504 +/- 399 mosmol/kg H2O, n = 14) than CR (2,840 +/- 176 mosmol/kg H2O, n = rats. This observation was not attributable to differences in creatinine clearance (CR, 1.30 +/- 0.24; H, 1.24 +/- 0.03 ml/min, NS, n = 4) or plasma AVP (CR, 12.75 +/- 1.44; H, 12.38 +/- 1.17 pg/ml, NS, n = 6) levels. These results therefore suggest that the action of AVP on the MAL, in addition to the effect on collecting tubules, is involved in maximal urinary concentration in rats.


2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Rubina Marzagalli ◽  
Soraya Scuderi ◽  
Filippo Drago ◽  
James A. Waschek ◽  
Alessandro Castorina

Enduring diabetes increases the probability of developing secondary damage to numerous systems, and these complications represent a cause of morbidity and mortality. Establishing the causes of diabetes remains the key step to eradicate the disease, but prevention as well as finding therapies to ameliorate some of the major diabetic complications is an equally important step to increase life expectancy and quality for the millions of individuals already affected by the disease or who are likely to develop it before cures become routinely available. In this review, we will firstly summarize some of the major complications of diabetes, including endothelial and pancreatic islets dysfunction, retinopathy, and nephropathy, and then discuss the emerging roles exerted by the neuropeptide pituitary adenylate cyclase activating polypeptide (PACAP) to counteract these ranges of pathologies that are precipitated by the prolonged hyperglycemic state. Finally, we will describe the main signalling routes activated by the peptide and propose possible future directions to focus on developing more effective peptide-based therapies to treat the major complications associated with longstanding diabetes.


1996 ◽  
Vol 149 (2) ◽  
pp. 287-295 ◽  
Author(s):  
C S Kovacs ◽  
C L Chik ◽  
B Li ◽  
E Karpinski ◽  
A K Ho

Abstract Pituitary adenylate cyclase-activating peptide (PACAP) and vasoactive intestinal peptide (VIP) share 68% homology and function as neurotransmitters or neuroendocrine factors. Although VIP immunoreactivity has been detected in bone cells, the presence of PACAP or PACAP receptors in bone has not been determined. In this study, we investigated the role of PACAP and VIP in regulating cAMP accumulation in the UMR 106 osteoblast-like tumor cell line. PACAP 27 (10−9 to 3 × 10−7 m), PACAP 38 (10−9 to 3 × 10−7 m) and VIP (10−8 to 10−6 m) stimulated cAMP accumulation up to eightfold. PACAP 27 was slightly more potent than PACAP 38, and both were tenfold more potent than VIP. Both PACAP- and VIP-stimulated cAMP accumulation were potentiated by 4β-phorbol 12-myristate 13-acetate, an activator of protein kinase C. Two PACAP antagonists, PACAP 6–27 (3 × 10−6 m) and PACAP 6–38 (3 × 10−6 m), blocked PACAP- and VIP-stimulated cAMP accumulation. Two VIP antagonists ([Lys1,Pro2,5,Arg3,4,Tyr6]-VIP, and 4 Cl-d-Phe6,Leu17]-VIP) did not reduce the PACAP-or VIP-stimulated cAMP accumulation. Pretreatment with PACAP 27, PACAP 38 or VIP equally blocked PACAP- and VIP-stimulated cAMP accumulation. These results suggest that PACAP is a more potent stimulator of cAMP accumulation than VIP in UMR 106 cells. PACAP and VIP may share a role in the paracrine or neuroendocrine regulation of bone metabolism. Journal of Endocrinology (1996) 149, 287–295


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