No abstract

Hydrocephalus is a common and potentially devastating birth defect affecting the CNS, and its relationship with G protein-coupled receptors (GPCRs) is unknown. We have expressed 2, 4, or 6 copies of a GPCR--the human PAC1 receptor with a 130-kb transgene in the mouse nervous system in a pattern closely resembling that of the endogenous gene. Consistent with PAC1 actions, PKA and PKC activity were elevated in the brains of Tg mice. Remarkably, Tg mice developed dose-dependent hydrocephalus-like characteristics, including enlarged third and lateral ventricles and reduced cerebral cortex, corpus callosum, and subcommissural organ (SCO). Neuronal proliferation and apoptosis were implicated in hydrocephalus, and we observed significantly reduced neuronal proliferation and massively increased neuronal apoptosis in the developing cortex and SCO of Tg embryos, while neurite outgrowth and neuronal migration in vitro remain uncompromised. Ventricular ependymal cilia are crucial for directing cerebrospinal fluid flow, and ependyma of Tg mice exhibited disrupted cilia with increased phospho-CREB immunoreactivity. These data demonstrate that altered neuronal proliferation/apoptosis and disrupted ependymal cilia are the main factors contributing to hydrocephalus in PAC1-overexpressing mice. This is the first report to our knowledge demonstrating that misregulation of GPCRs can be involved in hydrocephalus-related neurodevelopmental disorders.

Patients with bone cancer report severe pain and receive mu-opioids. We developed a family of peptidomimetic delta-agonists, one of which H2N-Tyr-dVal-Gly-Phe-Ala-OH ([dVal(L)2,Ala(L)5]E) binds with a 1700x affinity at the delta versus mu receptor. To examine the systemic analgesic efficacy of this delta-agonist versus morphine in osteosarcoma pain, osteosarcoma cells are injected into one femur of the anesthetized mouse. After 10-18 days, a decalcification of the injected femur occurs along with a pronounced tactile allodynia. IP morphine and [dVal(L)2,Ala(L)5]E produced a dose-dependent reversal of allodynia with the respective ED50 values being 5.3+/-1.9 mg/kg for morphine and 1.3+/-0.3 mg/kg for [dVal(L)2,Ala(L)5]E. Plotting peak effect versus area under the analgesic curve for doses of morphine and [dVal(L)2,Ala(L)5]E revealed overlapping curves suggesting that for a given effect, [dVal(L)2,Ala(L)5]E produced a similar duration of action as morphine. These effects were reversed by IP naloxone (3 mg/kg). IP naltrindole (1 mg/kg) preferentially reversed [dVal(L)2,Ala(L)5]E. The upper dose effects of morphine but not [dVal(L)2,Ala(L)5]E were limited by pronounced hyperactivity. No other effects were noted. These results show that IP [dVal(L)2,Ala(L)5]E through a delta receptor produces analgesia equal in efficacy to that of morphine but with a 4.5-fold greater potency. Over the doses examined, morphine actions were side effect limited. The delta side effects were not so limited, suggesting a favorable therapeutic ratio for delta-agonists in this pain model. These studies suggest that a systemically delivered delta-opioid agonist has pronounced analgesic properties on a preclinical cancer pain model.

[reaction: see text] We report here the enantioselective synthesis of Boc-alpha-methyl-d-cysteine(PMB)-OH and lanthionine building blocks through the regioselective ring opening of key intermediate Boc-alpha-methyl-d-serine-beta-lactone.

Left ventricular and regional vascular effects of halothane were assessed in dogs and primates in which coronary, mesenteric, renal, and iliac blood flows, arterial blood pressure, left ventricular diameter and pressure, dD/dt (i.e., the velocity of myocardial fiber shortening), and dP/dt were continuously measured in the control resting state, while the conscious animals were breathing O 2 , and during halothane-O 2 anesthesia maintained at 1% or at 2% for 90 minutes (separate experimental days). Halothane caused a concentration-dependent depression of myocardial contractility: (dP/dt)/P fell 68 ± 5% during 2% halothane anesthesia and left ventricular end-diastolic diameter rose. Halothane also caused a redistribution of regional blood flows. At a concentration of 1% halothane, the most intense vasodilatation occurred in the renal bed (renal resistance fell 46 ± 5%), but mesenteric resistance rose (42 ± 15%). With 1% halothane regional vascular resistances tended to rise with time, but with 2% halothane regional blood flows rose with time. A direct vasodilating action of halothane was observed following direct intra-arterial injection of the drug. Probably this action was responsible for the renal and iliac vasodilatations and for the opposition to the metabolically induced vasoconstriction in the coronary bed. Thus, the administration of the most commonly employed potent inhalation anesthetic, halothane, substantially alters myocardial contractility and regional blood flows and resistances. These effects are, in many instances, a function of the concentration of the anesthetic and the duration of its administration. KEY WORDSanesthesia renal flow mesenteric flow iliac flow myocardial contractility baboon chimpanzee