RESUMO
Endomorphin-1 and -2 (mu-opioid receptor agonists) produced a concentration-dependent and naloxone-sensitive inhibition of cholinergic contractile responses in guinea-pig trachea (at 10 microM, 46.1 +/- 8.0% and 33.8 +/- 8.6%, respectively). Endomorphin-1 and -2 also inhibited electrically-evoked acetylcholine release from cholinergic nerves innervating guinea-pig (at 0.1 microM, 41.8 +/- 10.9%; at 1 microM 60.1 +/- 6.3%, respectively) and human trachea (at 10 microM, 76.2 +/- 18.1%, and 77.7 +/- 14.3%, respectively). Naloxone prevented the inhibition by endomorphin-1 and -2 in both guinea-pig and human trachea, suggesting that these peptides can inhibit cholinergic, parasympathetic neurotransmission to the airways via the activation of classical opioid receptors.
Assuntos
Acetilcolina/metabolismo , Oligopeptídeos/farmacologia , Receptores Opioides mu/agonistas , Traqueia/efeitos dos fármacos , Animais , Relação Dose-Resposta a Droga , Cobaias , Humanos , Masculino , Contração Muscular/efeitos dos fármacos , Naloxona/farmacologia , Sistema Nervoso Parassimpático/efeitos dos fármacos , Traqueia/inervação , Traqueia/fisiologiaRESUMO
Data on growth and development are presented for eight litters of captive-born Phenacomys intermedius. Neonates from litters of four averaged 2.26 g at birth, significantly heavier than neonates from litters of five (1.96 g). Weights on day one showed a statistically significant decrease of 0.20 g per increase in litter size of one neonate. In general, large litters had lower growth rates. Growth of Phenacomys intermedius can be described by the equation Y = 1.17 + 0.62 X and the geometric growth constant is K = 0.079. Pinnae unfolded at 3.7 days, lower incisors erupted at 7.0 days, and eyes opened at 14.6 days. Data on growth and development are compared to other species of Phenacomys and to other microtines.
