To determine whether the cyclic adenosine monophosphate (cAMP) mediated protein kinase signal transduction pathway is involved in the pyrogenic action of corticotropin releasing hormone (CRH) in rats. Methods Corticotropin releasing hormone, 2', 3 '-dideoxyadenosine (DDA) and adenosine-3', 5' (cyclic) monophosphorothionate, Rp-lsomer (Rp-cAMPS), were administered intracerebroventricularly (i.c.v.). The colonic temperature was measured using a thermistor, and the content of cAMP in the hypothalamus was determined by radioimmunoassay. Hypethalemic incubation was used to assess the effects of CRH on the content of cAMP in the hypothalamus in vitro. Results Microinjection (i.c.v.) of CRH (2.5 μg, 5.0 μg and 10 μg) caused increases in colonic temperature and the hypothalemus cAMP level in conscious rats. CRH increased hypothalemus cAMP level in vitro. The pyrogenic effects of CRH were abolished or markedly inhibited by prior injection (i. c. v. ) of an adenylate cyclase inhibitor, DDA (30 μg), or an inhibitor of cAMP-dependent protein kinase, Rp-cAMPS (15 μg). Conclusion cAMP mediates the pyrogenic action of centrally administered of CRH in rats, and protein kinase A may play an important role in the central CRH-induced fever. The cAMP-dependent protein kinase signal transduction pathway may be involved in the central mechanisms of the pyrogenic action of CRH in rats.

Objective To assess the feasibility, efficiency and selectivity of adenovirus-mediated gene transfer to local arterial wall by protein-coated metallic stent. Methods A replication-defective recombinant adenovirus carrying the Lac Z reporter gene for nuclear specific β-galactosidase (Ad-βgal) was used in this study. The coating for metallic stent was made by immersing it in a gelatin solution containing crosslinker. The coated stents were mounted on a 4.0 or 3.0 mm percutaneous transluminal coronary angioplasty (PTCA) balloon and submersed into a high-titer Ad-βgal viral stock (2 × 1010 pfu/ml) for 3 min, and then implanted into the carotid artedes in 4 mini-swines and into the left anterior descending branch of the coronary artery in 2 mini-swines via 8F large lumen guiding catheters. The animals were sacrificed 7 (n=4), 14 (n = 1) and 21 (n = 1 ) days after implantation, respectively. The β-galactosidase expression was assessed by X-gal staining. Results The results showed that the expression of transgene was detected in all animal. In 1 of carotid artery with an intact intima, the β-gal expression was limited to endothelial cells. In vessels with denuded endothelium, gene expression was found in the sub-intima, media and adventitia. The transfection efficiency of medial smooth muscle cells was 38.6%. In 2 animals sacrificed 7 days after transfection, a microscopic examination of X-gal-stained samples did not show evidence of transfection in remote organs and arterial segments adjacent to the treated arterial site. Conclusions Adenovirus-mediated arterial gene transfer to endothelial, smooth muscle cells and adventitia by protein-coated metallic stent is feasible. The transfection efficiency is higher. The coated stent may act as a good carrier of adenovirus-mediated gene transfer and have a potential to prevent restenosis following PTCA.