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The profile of P2 receptor signaling in respiratory control has increased substantially since the first suggestions more than 15 years ago of roles in central chemoreception and modulating inspiratory motor outflow. Part of this reflects the paradigm shift that glia participate in information processing and that ATP is a major gliotransmitter. P2 receptors are a diverse family. Here, we review ATP signaling in respiratory control, highlighting G-protein coupled P2Y 1 receptors that have been a focus of recent work. Despite strong evidence of a role for glia and P2 receptor signaling in the central chemosensitivity mediated by the retotrapezoid nucleus, P2Y 1 receptors do not appear to be directly involved. Evidence that central P2 receptors and glia contribute to the hypoxic ventilatory response is compelling and P2Y 1 receptors are the strongest candidate. However, functional significance in vivo, details of the signaling pathways and involvement of other receptor subtypes remain important questions. [ABSTRACT FROM AUTHOR]

CASE PRESENTATIONA 48-year-old African-American man with chronic human immunodeficiency virus (HIV) infection since 1987 was referred to our center for renal transplant evaluation. HIV-associated nephropathy had been diagnosed 8 years earlier by renal biopsy. Hemodialysis had been initiated 3 years earlier. Past medical history was significant for hypertension and hyperlipidemia. Before transplantation, total cholesterol was 178 mg per 100 ml, low-density lipoprotein was 40 mg per 100 ml, and high-density lipoprotein was 67 mg per 100 ml without lipid-lowering therapy. The patient reported no history of earlier opportunistic infection (OI), malignancy, or co-infection with hepatitis B virus (HBV) or hepatitis C virus (HCV). He had been treated with highly active antiretroviral therapy (HAART) since 1990. After numerous treatment failures, virologic suppression was finally achieved with a combination of lamivudine, abacavir, efavirenz, and lopinavir/ritonavir. [ABSTRACT FROM AUTHOR]