The effects of a Chinese herb formula, anti-cancer number one (ACNO), on NK cell activity and tumor metastasis in rats.

The effects of anti-cancer number one (ACNO), a 19-herb Chinese formula used to treat cancer patients, were studied in F344 rats. In the first study, the number and activity of circulating NK cells were evaluated following 18 days of oral consumption of 0.1, 0.5, or 2 g/kg/day. The second study assessed the effect of ACNO on resistance to metastasis of the MADB106 tumor line, a syngeneic mammary adenocarcinoma that metastasizes only to the lungs and is highly sensitive to NK activity (NKA) in vivo. Resistance to metastasis was assessed under baseline conditions and following the administration of a beta-adrenergic agonist, metaproterenol (MP). MP was used to simulate sympathetic response to stressful conditions, and was previously shown to suppress resistance to MADB 106 metastasis. The results of the first study indicated a dose-dependent increase in NKA per ml of blood and per NK cell, with no significant changes in blood concentration of NK cells. In the second study, whereas MP caused a 4.5-fold increase in the number of metastases in untreated rats, only a 2.3-fold increase occurred in rats treated with ACNO. No significant improvement in baseline levels of resistance to metastasis was observed. These findings indicate the importance of studying ACNO under stressful conditions in patients with potentially metastasizing tumors. This may prove particularly important during the perioperative period, spanning from the detection of the primary tumor to postoperative treatment. During this critical period, psychological and physiological stress responses are known to cause massive immunosuppression, which was suggested to promote metastatic development.

Construction of antagonist dose-response curves for estimation of pA2-values by Schild-plot analysis and detection of allosteric interactions.

1. One aim of this paper is to show an alternative approach for the determination of antagonist affinity estimates, KB and pA2, by construction and evaluation of antagonist dose-response curves (DRCs), using the curve-fitting programme, ALLFIT. 2. Parallel antagonist DRCs were derived by vertical analysis of families of conventional agonist DRCs in the presence and absence of an antagonist at a certain agonist concentration above its ED50. The latter represents a chosen, i.e. fixed dose-ratio (DR). The antagonist concentration that reduces an agonist effect to its Emax/2 was termed Bx. It corresponds to B, the fixed antagonist concentration, tested to obtain DR-1, conventionally. 3. The dissociation constant was calculated as KB = Bx/DR-1, analogous to the conventional approach (KB = B/DR-1). Likewise, pA2-values were estimated by plotting log Bx, obtained by the alternative approach, vs log (DR-1) in an 'alternative Schild plot'. 4. Experimental agonist DRCs from our laboratory and from the literature were analysed and KB- and pA2-values obtained by the alternative approach were compared with those obtained by the conventional method. The results showed a very good agreement (correlation) between the pA2-values obtained by either method (slope = 1.02, r = 0.99, n = 9), in agreement with theoretical DRCs. 5. Besides estimation of KB and pA2, antagonist DRCs were also evaluated qualitatively. The most important finding was that allosteric antagonists or competitive antagonists with an allosteric component, such as gallamine, showed a significant reduction in the maximum of the antagonist DRCs (Imax). The evaluation of antagonist DRCs appears to be a sensitive procedure to detect allosteric interactions.6. This alternative approach can supplement or replace the conventional approach for the evaluation of antagonists on a quantitative and qualitative basis. The alternative approach appears of special advantage where the supply and/or the solubility of the agonist is limited, resulting in incomplete agonist DRCs.7. For rapid screening of potential antagonists, a single antagonist DRC at the maximum effective agonist concentration may be constructed to calculate KB reliably.

Cardiac postjunctional supersensitivity to beta-agonists after chronic chemical sympathectomy with 6-hydroxydopamine.

The sensitivity to sympathomimetic amines of isolated atria removed from sham-injected and 6-hydroxydopamine-treated (6-OHDA) guinea-pigs was examined in the presence of an extraneuronal uptake blocker and an alpha-adrenoceptor antagonist. Three weeks of pretreatment with 6-OHDA resulted in leftwards shifts of the dose-response curves for the positive chronotropic and inotropic responses of right and left atria to isoprenaline. The responses to the partial agonist salbutamol were also potentiated after 6-OHDA pretreatment, revealed as an increase in the maximum response relative to isoprenaline. The supersensitivity was post-synaptic in origin and independent of changes in disposition or metabolism, since it was observed with agonists immune to neuronal uptake and O-methylation, and in the presence of extraneuronal uptake inhibition by metanephrine. It was also specific for the beta-adrenoceptor, no supersensitivity to histamine being found. In the right atria, the supersensitivity was partially masked by an opposing depressant effect after 6-OHDA pretreatment which was observed with histamine. Dissociation constants (KA) for the left atrial inotropic responses to orciprenaline were determined by use of the antagonist Ro 03-7894. Atria from 6-OHDA-pretreated animals were supersensitive to orciprenaline, but the KA value did not differ from that after sham injection. It could therefore be concluded that the increase in sensitivity was not due to an increase in affinity for the beta-adrenoceptor.

In vitro effects of reproterol upon tracheo- bronchial, cardiac and cerebral adenylcyclase.

In vitro researches documented that reproterol, as well as salbutamol, is a powerful stimulant of adenyl cyclase activity in the trachea and bronchi but less potent than isoprenaline. The stimulation was antagonized by beta-blockers.

Ocular hypertensive response to beta-adrenoceptor agonists.

Acute administration of non-selective and relatively selective beta-adrenoceptor agonists elicit a monophasic fall in IOP. The present study indicates that unilateral application of certain beta-agonists on consecutive days can result in marked ocular hypertension. 1-Epinephrine, reproterol and 1-isoproterenol evoked an elevation of IOP on the second and third day after topical administration of a 2% solution in normal rabbits and in rabbits with surgically transected extraocular muscles. In contrast, the same concentration of d-isoproterenol produced hypotensive responses only when administered once daily for three consecutive days. Since d-isoproterenol did not cause a rise in IOP during chronic administration, the mechanism involved in the hypertensive response appears to be more sensitive to the levorotatory form. Administration of timolol inhibited the ocular hypertensive effect of epinephrine and reproterol. Since timolol lowers IOP by depressing formation of aqueous, it is suggested that the rise in IOP following chronic administration of beta-agonists possibly involves an increase in aqueous humor production.

The opposed influences of beta-adrenergic stimulation and adenosine on the frequency-force relationship of isolated left atria of guinea-pigs.

The normal frequency-force relationship of left guinea-pig atria can be largely suspended when strong beta-adrenergic stimulation by orciprenaline is antagonized by the negative inotropic effect of adenosine, so that contraction amplitude is nearly equal at an intermediate level over a wide range of stimulation rates. Curves obtained with new method for recording continuous frequency-force loops are presented.

Prevention by somatostatin of rise in blood pressure and plasma renin mediated by beta-receptor stimulation.

The interrelationships of increased plasma renin and elevated blood pressure following acute beta-stimulation by orcipernaline and its prevention by somatostatin was studied in normal man. During somatostatin infusion basal values of renin and blood pressure were unchanged. Following orciprenaline both variables increased significantly. Combination of somatostatin and orciprenaline reduced the rise in plasma renin activity by 49%, mean arterial blood pressure by 21% and heart rate by 19%, compared with beta-stimulation alone. The results indicate that the inhibitory action of somatostatin on plasma renin activity may be mediated via beta-receptors. The lesser increase of blood pressure under somatostatin plus orciprenaline also indicates a possible inhibitory effect of somatostatin on beta-adrenergic receptors.

Actions of some sympathomimetic bronchodilator and beta-adrenoceptor blocking drugs on contractions of the cat soleus muscle.

1. (-)-Isoprenaline, salbutamol, orciprenaline and quinterenol injected intravenously decreased the tension and degree of fusion of incomplete tetanic contractions of the soleus muscle of the anaesthetized cat.2. Under the most sensitive conditions, the smallest effective dose of (-)-isoprenaline was of the order of 0.01 mug/kg intravenously. Salbutamol was usually 6-10 times, orciprenaline 20-30 times and quinterenol about 35 times less potent than isoprenaline. The effects of salbutamol were about 1.6 times, of orciprenaline about 1.8 times and of quinterenol more than 20 times as long lasting as those of (-)-isoprenaline.3. The effects of the sympathomimetic amines were blocked by propranolol, H56/28, H35/25 and butoxamine but not by ICI 50172. The combined results with agonists and antagonists indicate that the receptors involved can be classified as of the beta(2) type.4. The effect of the amines on the cat soleus muscle appears to be analogous to that causing enhancement of physiological tremor in man, which suggests that skeletal muscle tremor may be an occasional unwanted side effect of the use of these bronchodilators.