We counted only the concentration of L-NAME which is able to produce a long-lasting BP change for at least 30?min after drug administration. attenuated by pretreatment with intra-OVLT injection of haloperidol, “type”:”entrez-protein”,”attrs”:”text”:”SCF23390″,”term_id”:”1052305664″,”term_text”:”SCF23390″SCF23390, or 6-hydroxydopamine. In the contrast, the hydroxylamine-, 8-Br-cGMP- or SNP-induced depressor effects were attenuated by pretreatment with intra-OVLT injection of amphetamine, SKF 38393 or apomorphine. The data suggest that activation of a NO-DA link pathway within the OVLT of rat brain exerts control over blood pressure. for at least 2 weeks before experiments. The light was turned on at 0600?h and turned off at 1800?h. Surgical preparation The Inolitazone animals were anaesthetized with urethane (1.4?g?kg?1, i.p.) and placed in a Kopf stereotaxic apparatus. For direct injection of drugs into the lateral cerebral ventricle or the OVLT, a stainless-steel cannula which consisted of a guide tube (0.81?mm outer diameter) with a snugly fitting trocar was implanted into the lateral cerebral ventricle (AP, ?0.8?mm; LAT, ?1.5?mm and DV, ?3.5?mm) or the OVLT (AP, ?0.5?mm; LAT, ?0.1?mm and DV, ?8.5?mm) according to the atlas and the coordinates of Paxinos & Watson (1982). Microinjection was made into the OVLT through a 26 gauge cannula connecting to a 10?l Hamilton microsyringe. The volume of fluid injected over 5?s was 5.0 or 0.5?l for intracerebroventricular (ICV) or intra-OVLT injection, respectively. For measurement of DA release, a nafion-coated carbon fibre electrode was implanted stereotaxically into the OVLT. Auxiliary (silver wire) and reference (Ag/AgCl) electrodes were placed on the dura surface of the parietal skull. Differential pulse voltammograms were then recorded automatically every 0.5?s (Lin & Yang, 1994). For assessment of cardiovascular functions, a fine catheter was inserted into the femoral artery and was connected a Statham blood pressure transducer to a Gould 4-channel polygraph for recording mean and pulsatile arterial blood pressure. Both the heart rate and blood pressure were measured. Drugs Drugs, administered into the OVLT included hydroxylamine (Sigma, 0.01?C?0.1?mg), sodium Inolitazone nitroprusside (SNP; sigma; 0.01?C?0.1?mg), NG-nitro-L-arginine methyl ester (L-NAME; RBI; 0.05?C?0.2?mg), 7-nitroindazol (7-NI; RBI; 0.1?mg) and aminoguanidine (RBI; 0.10?mg). All compounds were dissolved in saline. The drugs administered intracerebroventricularly included hydroxylamine (0.05?C?0.50?mg), L-NAME (0.1?C?1.0?mg), aminoguanidine (1.0?mg), SNP (0.10?C?0.50?mg), or 7-NI (1.0?mg). DA monitoring A multiple carbon fibre (28?m in diameter, AVCO, Lowell, MA, U.S.A.) was inserted into the pulled glass micropipette (20?C?25?mm in length). The tip was cut, and then carbon fibre Inolitazone was pushed out of the pipette tip. Electrical contact with the fibre was made using silver paste. The tip and blunt end of the pipette were sealed with cyanoacrylate adhesive (super glue). The entire surface of a pyrolytic carbon fibre was 12?m thick and 10025?m long. To improve the sensitivity Rabbit polyclonal to HOMER1 and selectivity of carbon fibre for DA, the electrodes were electrically pretreated as described previously (Lin & Yang, 1994). This treatment consisted of a DC current applied in two stages, 2.2?V for 30?s in 0.1?M H2SO4, and 2.2?V for 30?s in 0.1?M HCl. The carbon fibre electrode was washed with distilled water. The tip of the carbon fibre electrode was coated with 1% nafion solution (Aldrich Chemical Company, Inc, Milwaukee, WI, U.S.A.). The nafion-coated electrode was then dried at 60C for 20?s and used immediately for followed by measurements. Differential pulse amperometry was performed and with a Biopulse (Solea Tacussel Co., France) using the following scan parameters: imposed initial potential=?220?mV; imposed final potential=?70?mV; prepulse=70?ms; measuring pulse=40?ms; measuring potential=40?mV; and pulse cycle=25?s. The sensitivity of the nafion-coated carbon fibre electrode to catecholamines in the concentration range of 200?C?800?nm was determined using differential pulse.