ATP release from the carotid bodies of DBA/2J and A/J inbred mouse strains

The purposes of this study were to: (1) establish an effective method to measure the release of ATP from the mouse carotid body (CB) and (2) determine the release of ATP from the CB of the DBA/2 J (high hypoxic responder) and A/J (low hypoxic responder) mouse in response to hypoxia and hypercapnia. An incubation chamber was constructed utilizing a Costar® Spin-X Centrifuge Tube Filter. The filter was coated with low melting point agarose to hold 4 CBs or 4 superior cervical ganglia (SCG). Hypoxia did not increase ATP release from the CB of either strain. ATP increased in response to a normoxic/hypercapnic challenge in the DBA/2 J's CB but not in the A/J's CB. ATP release from the SCG was affected by neither hypoxia nor hypercapnia in both strains. Thus, we have concluded: (1) we successfully established a chamber system to measure ATP released from the mouse CB; (2) ATP may not be an excitatory neurotransmitter in the CB of these mice under hypoxia; (3) ATP may be a neurotransmitter in the CB of the DBA/2 J mouse strain during hypercapnia.