Open AccessBRONCHODILATING ACTIONS OF (±)-1-(3,4,5-TRIMETHOXY-BENZYL)-1,2,3,4-TETRAHYDR01S0QUIN0L1NE (TMI) DERIVATIVES IN ANESTHETIZED CATS
Author(s) -
Tomio Segawa,
Yoshihiro Nakata,
Haruaki Yajima,
Kouki Kitagawa
Publication year - 1977
Publication title -
japanese journal of pharmacology/japanese journal of pharmacology
Language(s) - English
Resource type - Journals
eISSN - 1347-3506
pISSN - 0021-5198
DOI - 10.1254/jjp.27.573
Subject(s) - bronchodilation , bronchoconstriction , chemistry , propranolol , potency , nifedipine , cats , pharmacology , heart rate , bioavailability , anesthesia , medicine , blood pressure , bronchodilator , calcium , biochemistry , in vitro , organic chemistry , asthma , airway
Crude mitochondrial P2 fractions from bovine hypothalamus and substantia nigra, slices from rabbit spinal cord and mesencephalon and glial fractions from rabbit brain were incubated with [3H]-substance P and the uptake was measured and compared with those for 5-HT and GABA. Substance P was to some extent taken up into the fractions but this uptake was neither temperature nor time dependent and the pellet/medium ratios were less than 1. Similar results were obtained in high potassium treated slices from rabbit mesencephalon. The rate of uptake for [3H]-substance P increased linearly in proportion to the medium concentration, suggesting a non-saturable binding. These results, together with our previous observations provide strong evidence that nerve terminals and glial cells lack a temperature sensitive, active uptake system capable of terminating transmitter action of substance P at the synapse.