Fig. 4.

Chronic antibiotic administration and faecal microbiota transfer do not alter cardiorespiratory responses to phenylbiguanide administration in anaesthetised rats.

a) Representative traces of blood pressure (red indicates mean value), heart rate, tracheal airflow, raw and integrated diaphragm (Dia) electromyogram (EMG) activity and arterial oxygen saturation (SaO₂) during intravenous administration of 5-HT₃ agonist phenylbiguanide (PBG; 8 μg/kg) indicated by the upwards arrow. Group data for maximum apnoea duration (b, f) and tachypnoea (c, g) normalised to baseline respiratory period in response to 2,4, 8, 16 and 32 μg/kg of PBG for VEH and ABX (b, c) and for VEH-FMT and ABX-FMT rats (f, g). Absolute change in mean arterial blood pressure (MAP; d, h) and heart rate (e, i) in response to 2,4, 8, 16 and 32 μg/kg of PBG for VEH and ABX (d, e) and for VEH-FMT and ABX-FMT rats (h, i). VEH, autoclaved deionised water; ABX, antibiotic-treated; VEH-FMT, VEH followed by faecal microbiota transfer; ABX-FMT, antibiotic-treated followed by faecal microbiota transfer. Data (b-i) are expressed mean ± SD; VEH (n = 8), ABX (n = 8), VEH-FMT (n = 9) and ABX-FMT (n = 10). Groups were statistically compared by two-way ANOVA for VEH and ABX and separately for VEH-FMT and ABX-FMT. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)