title: [Adrenoreceptive structures in the early embryos of the clawed toad (Xenopus laevis)].
abstract: Studies have been made on the binding of labeled ligands to beta-adrenoreceptor--3H-dihydroalprenolol (DHA) and 125I-iodocyanopindolol (ICP--in crude homogenate and subcellular fractions of toad embryos during cleavage divisions. Specific binding of these ligands was observed which is confirmed by a decrease of the activity after addition of cold propranolol or adrenalin. The value of Kd for DHA is equal to 3 x 10(-9) M for ICP--to 1.5 x 10(-9) M. In addition to this high-affinity pool of binding with a low capacity, a low-affinity and high-capacity pool was also found. Cooling of the preparation up to 4 degrees C for 2 h increases the specific binding simultaneously with a decrease of the affinity of adrenoreceptive structures of the embryo. The data obtained are discussed in relation to the criteria of intracellular transmitter process.
authors.forename: Iu B
authors.initials: IuB
authors.lastname: Shmukler
authors.forename: N G
authors.initials: NG
authors.lastname: Grigor'ev
authors.forename: G N
authors.initials: GN
authors.lastname: Moskovkin
mesh_terms: D000818:Animals; D002970:Cleavage Stage, Ovum / Q000378:metabolism; D004082:Dihydroalprenolol / Q000493:pharmacokinetics; D004837:Epinephrine / Q000493:pharmacokinetics; D007457:Iodine Radioisotopes; D020120:Iodocyanopindolol; D008024:Ligands; D008928:Mitochondria / Q000378:metabolism; D010869:Pindolol / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D011433:Propranolol / Q000493:pharmacokinetics; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D013696:Temperature; D014316:Tritium; D014982:Xenopus laevis / Q000196:embryology / Q000378:metabolism*
chemical_list: D007457:Iodine Radioisotopes; D008024:Ligands; D011943:Receptors, Adrenergic, beta; D014316:Tritium; D004082:Dihydroalprenolol; D020120:Iodocyanopindolol; D011433:Propranolol; D010869:Pindolol; D004837:Epinephrine
vernacular_title: Adrenoretseptivnye struktury v rannikh zarodyshakh shportsevoĭ liagushki (Xenopus laevis).