The pharmacological cocktail used to synaptically isolate pacemaker neurons contained 20 μM 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), 10 μM DL-2-amino-5-phosphonovaleric acid (AP5), 1 μM strychnine, and 10 μM bicuculline (all from Sigma).
Substance P (SP, Sigma) and the μ opioid receptor agonist D-Ala2-N-Me-Phe4-Glycol5-enkephalin (DAMGO, Sigma) were dissolved in aCSF and bath-applied at their final concentration of 0.5 μM and 0.25 μM, respectively. A single modulatory drug was applied per preparation in order to avoid cross effects. Preparations were exposed to a drug for a 15 min period and its effects on respiratory rhythm cycle frequency were analyzed at the end of this period using Clampfit software (Molecular Devices). The reversal of any observed effects was tested for each drug after a 30 min period wash-out during which fresh aCSF was superfused in the recording chamber.
Values are given as mean ± SEM. Student's t tests with a Mann-Whitney Rank Sum test or ANOVA tests were used to assess differences (taken to be significant at P < 0.05) between values in the presence of the drugs and controls.
Substance P (SP, Sigma) and the μ opioid receptor agonist D-Ala2-N-Me-Phe4-Glycol5-enkephalin (DAMGO, Sigma) were dissolved in aCSF and bath-applied at their final concentration of 0.5 μM and 0.25 μM, respectively. A single modulatory drug was applied per preparation in order to avoid cross effects. Preparations were exposed to a drug for a 15 min period and its effects on respiratory rhythm cycle frequency were analyzed at the end of this period using Clampfit software (Molecular Devices). The reversal of any observed effects was tested for each drug after a 30 min period wash-out during which fresh aCSF was superfused in the recording chamber.
Values are given as mean ± SEM. Student's t tests with a Mann-Whitney Rank Sum test or ANOVA tests were used to assess differences (taken to be significant at P < 0.05) between values in the presence of the drugs and controls.