Increases in arterial blood pressure and heart rate produced by microinjection of antisense nNOS oligonucleotide into the nucleus tractus solitarii

In the present study, we investigated the cardiovascular effects of bilateral microinjection of an antisense nNOS (neuronal nitric oxide synthase) oligonucleotide into the nucleus tractus solitarii (NTS). The antisense was designed to target a region of the rat nNOS mRNA that contains the initiation codon, with a sequence of 5'-CTTCCATGGTATCTGTG-3'; and its corresponding sense sequence (5'-CACAGATACCATGGAAG-3') and scrambled sequence (5'-CGTAGTAGGCATACGTA-3') were designed. The oligonucleotide was diluted in artificial cerebrospinal fluid and mixed with cationic lipids for transfection. Bilateral microinjection of antisense nNOS oligonucleotide (20 pmol/50 nl) into the NTS in urethane-anesthetized, paralyzed Wistar-Kyoto rats (n = 7) produced a significant increase in arterial blood pressure 30-60 min after the microinjection as compared with the changes produced by bilateral microinjection of sense nNOS oligonucleotide (n = 5) or scrambled oligonucleotide (n = 5) into the NTS. Bilateral microinjection of the antisense nNOS produced a significant increase in heart rate 30 min after the microinjection as compared with the change produced by bilateral microinjection of the sense nNOS. Immunohistochemical study showed that nNOS in the NTS was inhibited by the microinjection of the antisense. These results suggest that expression of the nNOS gene in the NTS may regulate circulation.