Resumo

BORGES, A et al. Presencia de Guanilil Ciclasas sensibles a los Péptidos Natriuréticos Anp y Cnp en el Músculo Liso Traqueal de Bovino. RFM [online]. 2002, vol.25, n.1, pp.73-75. ISSN 0798-0469.

Cyclic GMP production in bovine airway smooth muscle (BASM) is mediated through soluble (sGC) and membrane-bound (mGC) guanylyl cyclases. A muscarinic-sensitive mGC exists in BASM which activity is regulated dually by M₂- and M₃-receptor subtypes. To identify the mGC involved in muscarinic regulation of BASM tone, RT-PCR from total RNA was performed using degenerate oligonucleotides designed for a conserved region within the GC catalytic domain. Sequencing of products revealed that 76% of all transcripts corresponded to the sGC b1 subunit and 24% to the B-type (CNP-sensitive) mGC. cGMP production by BASM plasma membrane and soluble fractions confirmed that sGC activity is 3-fold with respect to mGC activity. RT-PCR using isoform-specific oligonucleotides showed that ANP-sensitive and guanylyn-sensitive mGCs are also expressed in BASM. mGC activity was significantly (p < 0.001) stimulated by CNP over ANP (with guanylyn showing little or no effect), indicating that the predominant mGC BASM isoform is CNP-sensitive.

Palavras-chave : Guanilil ciclasa; Músculo liso de las vías aéreas; Péptido natriurético.