According to the adenoma-carcinoma sequence, colon cancer results from accumulating somatic gene mutations; environmental growth factors accelerate and augment this process. For example, diets rich in meat and fat increase fecal bile acids and colon cancer risk. In rodent cancer models, increased fecal bile acids promote colon dysplasia. Conversely, in rodents and in persons with inflammatory b...

The characterization of pharmacological receptors in subcellular preparations has, to date, relied mainly on observations of the binding properties of radioactively labelled ligands. Minimal criteria for receptor-specific binding are that a component of binding should saturate with increasing concentrations of the ligand and that only drugs with the appropriate pharmacological specificity, and ...

Interactions of several muscarinic drugs with their receptors were studied in the ciliary body smooth muscles of the rabbit. The ciliary body smooth muscles responded to carbachol, a muscarinic full agonist, with concentration-dependent contractions, and the pD2 value of carbachol was 5.16 +/- 0.05. Atropine, a competitive antagonist of muscarinic receptors, produced a parallel shift to the rig...

BACKGROUND The subject of the study was determination of the effect of drugs on ileal smooth muscle contraction induced by activation of M(1) type muscarinic receptors. Drugs that have an effect on muscarinic receptors are divided to agonists, with close ties to the receptor and high internal activity and antagonists, with no internal activity. Conducted experiments tested interactions between ...

Muscarinic acetylcholine receptors contain a region encompassing the second and third transmembrane domains that is rich in conserved aspartic acid residues. To investigate the role of four conserved aspartic acids at positions 71, 99, 105, and 122 in muscarinic receptor function, point mutations in the rat m1 muscarinic receptor gene were made that converted each Asp to Asn, and wild type or m...

The external globus pallidus (GPe) is central for basal ganglia processing. It expresses muscarinic cholinergic receptors and receives cholinergic afferents from the pedunculopontine nuclei (PPN) and other regions. The role of these receptors and afferents is unknown. Muscarinic M1-type receptors are expressed by synapses from striatal projection neurons (SPNs). Because axons from SPNs project ...

mirtazapine is a new antidepressant that can increase noradrenergic and serotonergic neurotransmission. it is also a postsynaptic antagonist of 5-ht2 and 5-ht3. in addition, it has only a weak affinity for 5-ht1 receptors and has very weak muscarinic anticholinergic and histamine (h1) antagonist properties. we report a case of hypertensive urgency that ensued after a patient took a single low d...

The venom of the Eastern green mamba from Africa, Dendroaspis angusticeps, was found to block the binding of 3H-quinuclidinyl benzilate to pure m1 and m4 muscarinic ACh receptors expressed in Chinese hamster ovary cells. The principal toxin in the venom with anti-m1 muscarinic activity was purified by gel filtration and reversed-phase HPLC. This toxin has 64 amino acids, a molecular mass of 736...

Receptor activation results in homologous regulation and can also affect other types of receptors (a process that has been reported to heterologous regulation). Heart cells express subtypes of muscarinic receptors and adrenoceptors, almost antagonistic in their action (M2 muscarinic receptors and beta1-adrenoceptors). Therefore, they provide an excellent model of heterologous regulation. Moreov...