A series of 1-phenyl-3-amino-1,2,3,4-tetrahydronaphthalenes (1-phenyl-3-aminotetralins, PATs) previously was found to modulate tyrosine hydroxylase activity and dopamine synthesis in rodent forebrain through interaction with a binding site labeled by [(3)H]-(-)-(1R,3S)-trans-H(2)-PAT. Recently, we have discovered that PATs also bind with high affinity to the [(3)H]mepyramine-labeled H(1) receptor in rat and guinea pig brain. Here, we report the synthesis and biological evaluation of additional PAT analogues in order to identify differences in binding at these two sites. Further molecular modifications involve the pendant phenyl ring as well as quaternary amine compounds. Comparison of about 38 PAT analogues, 10 structurally diverse H(1) ligands, and several other CNS-active compounds revealed no significant differences in affinity at [(3)H]-(-)-trans-H(2)-PAT sites versus [(3)H]mepyramine-labeled H(1) receptors. These results, together with previous autoradiographic brain receptor-mapping studies that indicate similar distribution of [(3)H]-(-)-trans-H(2)-PAT sites and [(3)H]mepyramine-labeled H(1) receptors, suggest that both radioligands label the same histamine H(1) receptors in rodent brain. We also report a revision of our previous comparative molecular field analysis (CoMFA) study of the PAT ligands that yields a highly predictive model for 66 compounds with a cross-validated R(2) (q(2)) value of 0.67. This model will be useful for the prediction of high-affinity ligands at radiolabeled H(1) receptors in mammalian brain.
Nutritional support is essential in treating patients with gastroparesis. Initially, dietary changes should be instituted to reduce extra fat and bulk, and patients should be encouraged to eat frequent small meals with liquid supplementation. Enteral feeding should be introduced in the event of weight loss or persistent vomiting. Medical therapy is usually necessary early in treatment. Cisapride is the initial agent of choice and may be combined with an antiemetic agent, such as promethazine or chlorpromazine or, if side effects occur, ondansetron and granesitron. If cisapride is ineffective or contraindicated, metoclopramide is a reasonable option, though limited by side effects. Erythromycin is useful in the acute treatment of postoperative ileus and hospitalized gastroparetic patients, but its role is limited based on concerns about poor long-term effectiveness and antimicrobial resistance. Once domperidone becomes available in the United States, it will be useful for its promotility and antiemetic qualities. Combination therapy should be considered if monotherapy with cisapride or metoclopramide alone is ineffective. While not yet well studied, combination therapy has the potential to offer dramatic benefit for patients with refractory gastroparesis. Metoclopramide may be added to cisapride for patients with breakthrough symptoms or refractory chronic symptoms. Other combinations include metoclopramide with erythromycin, domperidone with cisapride, and domperidone with erythromycin. In the future, gastric pacing may become an effective option for patients not responding to medical therapy. Total gastrectomy should be performed only for end-stage gastroparesis when all other therapy has failed. Both procedures should be reserved for centers that specialize in severe gastric motility disorders.
Livers from mallards (Anas platyrhynchos) were treated with either β‐naphthoflavone (50 mg/kg) or phenobarbital (70 mg/kg). Purification of induced hepatic cytochrome P450 was accomplished using both DEAE and hydroxyapatite columns, as well as sodium dodecyl sulfate polyacrylamide gel electrophoresis separation. Polyclonal antibodies to these proteins were then produced in young male New Zealand White rabbits. β‐Naphthoflavone (βNF)‐ and phenobarbital (PB)‐treated red‐winged blackbird, screech owl, European starling, and lesser scaup liver microsomes were analyzed in western blots for species cross‐reactivity. Although all four of these avian species exhibited cross‐reactivity with antibodies to βNF‐induced mallard P450, all but the lesser scaup revealed a protein of higher molecular weight than that of the βNF‐induced mallard. In addition, only the lesser scaup exhibited cross‐reactivity with the anti‐PB‐induced mallard P450 antibodies.
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