Parasympathetic and adrenergic contractile responses in canine trachea and bronchus.

We compared the sympathetic and parasympathetic contractile responses of tracheal and third-order bronchial smooth muscle simultaneously in 26 dogs in situ. Stimulus-response curves were generated by bilateral stimulation of the cervical vagus nerves in five dogs to determine the parameters (20 V, 15 Hz, 2-ms duration) causing maximal parasympathetic contraction in trachea and bronchus. In six adrenal-intact (ADi) and five adrenalectomized (ADx) dogs, sympathetically mediated alpha-adrenergic contraction was studied after muscarinic and beta-adrenergic blockade by administering intravenous (iv) 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP). In ADi dogs, the maximal alpha-adrenergic contractile response to iv DMPP was 67.3 +/- 14.8% of the maximal parasympathetic response in trachea and 112 +/- 21% of the maximal parasympathetic response in bronchus (P less than 0.03). In ADx dogs, the maximal alpha-adrenergic-to-parasympathetic stimulation ratios were 17.6 +/- 1.3% in trachea and 41.4 +/- 2.5% in bronchus (P less than 0.001). Comparable relationships were also obtained in pharmacological studies of alpha-adrenergic and cholinergic responses in trachea and bronchus. We conclude that there is substantial heterogeneity in the physiological and pharmacological cholinergic and alpha-adrenergic contractile properties in trachea and bronchus. Relative to cholinergic contraction, both circulating catecholamines and sympathetic innervation cause substantially greater alpha-adrenergic contraction in bronchus than for tracheal smooth muscle.

Comparative distribution of smooth muscle postsynaptic contractile responses in canine trachea and bronchus in vivo.

The response of canine tracheal and bronchial smooth muscle to i.a. administered agonists causing smooth muscle contraction was compared in 22 mongrel dogs in vivo. Tracheal and bronchial contractile responses were measured isometrically in situ in the same dogs. In nine dogs, dose-response curves were generated with i.a. acetylcholine and histamine (10(-10) to 10(-6) mol) in a 4-cm tracheal segment and a 1-cm segment of third order bronchus. The tracheal response to i.a. histamine was 36.5 +/- 4.48% of the response to equivalent doses of acetylcholine. In bronchus, the contraction caused by histamine was 81.0 +/- 2.83% of the cholinergic contractile response (P less than .001). In five dogs having beta adrenergic blockade with propranolol, tracheal contraction to 10(-8) to 10(-6) mol i.a. norepinephrine was 27.3 +/- 4.2% of the response to acetylcholine. However, in bronchus, contraction to norepinephrine was 218 +/- 16.6% of the response to equivalent doses of acetylcholine (P less than .001). Phentolamine (200-400 micrograms/kg i.a.) caused 79 to 100% blockade of the tracheal and bronchial response to i.a. norepinephrine. Cholinergic contraction was blocked specifically with 5 micrograms/kg i.a. of atropine. It is concluded that there is substantial heterogeneity in the contractile responses of canine trachea and bronchus in situ. Relative to cholinergic contraction, both histamine and alpha adrenergic stimulation cause substantially greater contraction of airway smooth muscle in the third order bronchus than in trachea.

Physiological and pharmacological response of canine bronchial smooth muscle in situ.

We studied the isometric response of bronchial smooth muscle in a single third-order bronchus of 24 dogs in situ. Length-tension studies were performed in six dogs by repeated injection of 10(-5) mol acetylcholine (ACh) into the right bronchoesophageal artery, and the resting tension (30.6 +/- 6.9 g/cm) and length (0.76 +/- 0.14 cm) permitting maximal contraction were determined. In eight other dogs, dose-related bronchial contraction was obtained with 10(-10) to 10(-5) mol intra-arterial (ia) ACh. Supramaximal electrical stimulation of the right cervical vagus nerve and bronchial parasympathetic ganglion stimulation with ia 1-1-dimethyl-4-phenylpiperazinium (DMPP) also caused bronchial contraction. The maximal response to ia ACh (28.5 +/- 1.7 g/cm), supramaximal electrical stimulation (15.2 +/- 1.1 g/cm), and ia DMPP (10.5 +/- 3.0 g/cm) was blocked by an ia dose of atropine (1-5 micrograms/kg) that did not alter the sympathetic relaxation response in the trachea. In four dogs, the bronchial response to sympathetic activation was studied by intravenous (iv) bolus injection of DMPP after cholinergic blockade with atropine. DMPP (25 micrograms/kg iv) caused 9.5 +/- 2.2 g/cm bronchial relaxation, which was blocked completely by 2-4 mg/kg iv propranolol. In six other dogs, hypoxia induced by ventilation with pure nitrogen caused bronchial contraction, which was blocked by vagotomy, atropine, and hexamethonium. We report a sensitive method for selective measurement of bronchial smooth muscle response in a single resistance bronchus. This preparation preserves regional innervation and circulation and permits selective physiological stimulation in situ.

Sympathetic inhibition of histamine-induced contraction of canine trachealis in vivo.

The effect of sympathetic stimulation on histamine-induced tracheal contraction was studied in 42 dogs in situ. After cholinergic blockade with atropine, dose-response curves to intra-arterial (ia) histamine (10(-10)-10(-6) mol) were performed in 11 adrenal-intact (ADi) and 5 adrenalectomized (ADx) dogs receiving steady-state sympathetic stimulation from continuous intravenous infusion (62.5-312 micrograms . kg-1 . min-1) of 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP). In ADi dogs receiving maximal sympathetic prestimulation (312 micrograms . kg-1 . min-1 DMPP), tracheal tension barely exceeded base-line resting tension after 10(-6) mol ia histamine. In five dogs, tracheal tension after maximal sympathetic prestimulation exceeded base line for greater than or equal to 10(-8) mol ia histamine. In 12 other dogs, reversal of histamine-induced contraction by maximal sympathetic prestimulation was studied. Tracheal tension decreased 45.6 +/- 4.4 g/cm in four ADi dogs (P less than 0.001), 12.4 +/- 2.8 g/cm in four ADx dogs (P less than 0.02), and 2.2 +/- 2.5 g/cm in four control dogs receiving sham infusions (P greater than 0.90). No evidence was found for nonadrenergic relaxation of canine airway smooth muscle. We conclude that tracheal sympathetic nerves cause significant antagonism of histamine-induced contraction, which is augmented by adrenal secretion. We also report a pharmacological method for dose-related steady-state sympathetic stimulation of canine airways.

The immune response in humans and rabbits to monomeric and polymeric grass allergens.

The antigenicity of polymerized grass (PG) and monomer grass (MG) was studied. As compared with MG, PG produces a similar immunologic response in rabbits as demonstrated by a tanned red blood cell (TRBC) passive hemagglutination assay or by total serum binding of perennial rye grass Group I antigens (RGGI). Six patients with allergic rhinitis sensitive to several grass pollens received an average of 60,000 protein nitrogen units (PNU) or PG. The initial dose was 100 PNU ans a maintenance dosage of 8500 PNU was obtained after six injections without systemic reactions in any of the patients. Serum binding of RGGI increased significantly in the PG-treated patients and this increase was quantitatively similar to that measured in a second group of six atopic patients previously treated for 1 year with a total of 100,000 PNU of a standard grass extract mixture. PG, like polymerized ragweed (PRW), has a reduced allergenicity while retaining immunogenicity. These data suggest that PG as compared to standard aqueous grass extract mixtures represents an improved form of immunotherapy for the atopic patients.

A double-antibody radioimmunoassay for specific IgE to ragweed antigen E.

A double-antibody radioimmunoassay has been developed for quantitating IgE-a-AgE in serum. The patient's IgE is complexed by rabbit anti-human IgE, which is then precipitated with GARG. Radiolabeled AgE is then added to the washed precipitate and is specifically bound by IgE-a-AgE. This assay is highly reproducible, and unlike specific IgE assays based on the RAST concept, it cannot be inhibited by specific antibody of other immunoglobulin classes (blocking antibody). In addition, the double-antibody method does not require the use of myeloma IgE, and its results correlate well with those of a previously developed polystyrene tube method.

Further studies on the safety of polymerized antigens for immunotherapy.

Six patients receiving immunotherapy with standard aqueous extracts for the treatment of atopic disease were selected from the patient population of Northwestern University Allergy Clinics for continued immunotherapy with polymerized antigens. These six patients could not tolerate quantities of conventional aqueous extracts considered maintenance doses because of immediate-type local or systemic allergic reactions or both to immunotherapy. These six patients were treated with separate preparations of polymerized ragweed (PRW) and polymerized grass (PG), and each of the six patients was rapidly advanced to previously unobtainable maintenance doses of PRW and PG without local or systemic reactions. Treatment with other aeroallergen standard extracts was continued to maintenance dosage without further systemic reactions. In patients highly sensitive to ragweed and grass aqueous extracts, the substitution of these extracts with PRW and PG allows these patients to receive therapeutic immunotherapy injections with decreased risk of immediate-type local and systemic reactions.

Polymerized tree pollen antigens.

Aqueous extracts of tree pollen were partially purified and polymerized with methods previously established for preparation of ragweed and grass polymers. The polymerized tree preparations were antigenic as demonstrated by ability to elicit immediate-type skin reactivity in humans and to induce an immune response in rabbits. The polymerized tree antigen was 100- to 10,000-fold less skin reactive than monomer tree antigen in tree pollen-sensitive patients but both preparations had similar antigenicity in rabbits. These results demonstrate that polymerized tree antigens can be prepared and should have the therapeutic potential already demonstrated for polymerized ragweed preparations.