Muscarinic cholinergic receptors have been identified and characterized by radioligand binding studies in human peripheral lung tissue. The tissue was obtained at thoracotomy of 12 patients, of whom four had chronic obstructive lung disease. The radioligand 1-quinuclidinyl [phenyl-4-3H]benzilate (3H-QNB) was used to label the muscarinic cholinergic receptors. Binding was saturable, protein dependent and showed a high affinity and stereospecificity. Specific binding could be inhibited by agonists and antagonists; molar inhibition constants determined for the agents used were of the same order of magnitude as those reported for 3H-QNB inhibition in various tissues of laboratory animals. Inhibition experiments with agonists resulted in Hill slopes which were significantly different from unity, indicating multiple binding sites. The stable GTP analogue guanyl-5'-imidodiphosphate had no effect on the Hill slopes of agonists or antagonists. The number of binding sites was significantly less in lung tissue from patients with chronic obstructive lung disease.
TERPSTRA, G. K. AND J. L. SLANGEN. Central blockade of(methyl-) atropine on carbachol drinking: a dose-response study. PHYSIOL. BEHAV. 8 (4) 715--719, 1972. Administration of carbachol in the tractus diagonalis in rats elicited drinking and no eating. Norepinephrine administered in the same place did not induce drinking or eating. The specific drinking response induced by stimulation with 7.2 nmol (= 1.3 ~tg) of carbachol was gradually inhibited by preceding injections of graded doses of atropine and methylatropine at the same site. A 90 % inhibiting action of atropine and methylatropine was possible with a 3-10 times lower dose (0.18 ~tg) than used in earlier studies. Significant differences between the inhibition by atropine and methylatropine could not be demonstrated. A possible difference in inhibition at the lowest dose of atropine and methylatropine used (= 0.04 p~g) was discussed. Water intakeCarbachol stimulation Dose-response relationship Tractus diagonalisAtropine Methylatropine LOCAL stimulation of different parts of the limbic system of the rat with cholinergic substances, like carbachol and acetylcholine, elicits water drinking in water satiated rats [4,7,8].A dose response curve for the water intake elicited by injection of carbachol in the feeding-drinking area of the hypothalamus has been established. A maximal intake of water occurred after administration of 2.4 × 10-°M of carbachol (= 0.4 ~g)[16]. Levitt et aL [15] found for a number of different structures a maximal effect with a dose of 1 ~g of carbachol. Detailed observations have been made concerning the role of the preoptic and septal area in the elicitation of drinking behavior after local administration of carbachol [3,5,14].Carbachol-elicited drinking was inhibited by atropine when administered systemically [9,18]. On the other hand atropine not only blocked the effect of carbachol when administered in the same brain region as carbachol [9,14,19], but also when administered in another brain region in the limbic system [14].On the assumption that drinking elicited by carbachol is the result of activation of a cholinergic system, atropine, administered peripherally as well as centrally, has been used by several authors in order to block the effects of carbachol administered in the septal area. These results have been obtained by using about equal dosages of carbachol and atropine (tzg). It is not known however whether these doses of atropine axe likely to block only the stimulated parts of the cholinergic drinking system or other cholinergic systems affecting behavior as well. To answer that question information about the dose response relationship of carbachol elicited drinking and atropine is needed. To investigate this relationship in all areas of the limbic system that are supposed to play a role in the regulation of water intake is simply prohibiting. In our experiments we therefore concentrated on the anterior part of the preoptic area which is believed to be a part of the limbic drinking circuit [5].The purpose of the following ...
Summary-Therole of the tractus diagonalis in drinking behaviour induced by central chemical stimulation, 23-hr water deprivation and injection of a hypertonic sodium chloride solution was investigated by means of central and peripheral administration of atropine and methylatropine. The effect of the same doses of centrally and peripherally administered anticholinergics was greater on carbachol-induced drinking than on deprivation-induced drinking. Salt-induced drinking was only influenced by peripheral administration of the anticholinergics.The results indicate the presence of a central cholinergic and a peripheral cholinergic active mechanism in carbachol-induced drinking; a central cholinergic, a peripheral cholinergic and a non-cholinergic mechanism in deprivation-induced drinking; and a central cholinergic, a peripheral cholinergic and a non-cholinergic mechanism in salt-induced drinking. It is concluded that a cholinergic system cannot be the system that has an overall control over water intake behaviour. The results obtained make it questionable whether the tractus diagonalis has a specific function in the series of events that lead to water intake after water deprivation or a salt injection.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.