Plasma S1P levels in mice prior to (0 h), 4 h, or 10 h following torpor induction with 5′-AMP (7.5 mmol/kg) or at 4 h after administration of the A2BR agonist LUF6210 (3 mg/kg; A). Peripheral blood lymphocyte counts (B), T lymphocyte counts (C), and B lymphocyte counts (D) in mice during torpor (4 h post-5′-AMP administration) or following return to euthermia in mice (10 h post-5′-AMP administration) that were given the S1P1-specific antagonist W146 (10 mg/kg) compared with untreated controls. Bars represent mean ± sem; */** = P < 0.05/0.01, respectively (n=6–9 animals/group).