Vasorelaxing actions of molsidomine and its metabolites, in comparison with nitroglycerin.

The effect of a novel antianginal agent, molsidomine (N-ethoxycarbonyl-3-morpholinosydnonimine) (SIN-10) and its metabolites, 3-morpholinosydnonimine (SIN-1) and N-nitroso-N-morpholinoaminoacetonitrile (SIN-1A) on isolated dog blood vessels were investigated. SIN-1 and SIN-1A elicited a concentration-dependent relaxation of prostaglandin F2 alpha, contracted strips, while SIN-10 was without effect even in a concentration of 10(-4) M. The mean effective concentration (EC50) values of SIN-1A were much lower than SIN-1 and other vasodilators including nitroglycerin.

Effects of Met-enkephalin on the substance P-ergic and cholinergic responses in the rabbit iris sphincter muscle.

In the rabbit iris sphincter muscle, transmural electrical stimulation produces a substance P-ergic response, in addition to a cholinergic one. The substance P-ergic response was selectively attenuated or abolished by (D-Pro2, D-Trp7,9) substance P or trigeminal denervation. In the present work, the effects of Met-enkephalin on these two neurogenic responses were examined.

An experimental study on the effect of fluorocarbon on the preservation of free skin flaps in the rabbit.

Extensive experience with replantation and transplantation surgery has accrued since the development of microvascular surgery. However, circulation often fails to return to a tissue after a temporary period of vascular obstruction, even if the vascular anastomoses are perfect. This circulation failure is known as the "no-reflow phenomenon.

Effects of the sympathoadrenal system on vagally induced gastric acid secretion and mucosal blood flow in rats.

Effects of the sympathoadrenal system on vagally induced increases in gastric acid secretion and mucosal blood flow (MBF) were studied in anesthetized, gastric fistula rats. Greater splanchnic nerve stimulation reduced significantly both the gastric acid secretion and MBF. Stimulation of the splanchnic postganglionic nerve reduced to a greater extent the acid secretion than the MBF, while stimulation of the adrenal branch reduced both the acid secretion and MBF.

Nicotine-induced response in guinea-pig aorta enhanced by goniopora toxin.

The possible involvement of sodium action potentials in sympathomimetic effects of nicotine was investigated using isolated guinea-pig aortas. Goniopora toxin (GPT), a polypeptide isolated from coral, was used to increase the sodium influx through the fast sodium channel of the postganglionic sympathetic nerves; tetrodotoxin (TTX) was used to block this flux. Nicotine (10-300 microM) produced sympathetic nerve-mediated contractions in a concentration-dependent manner.

Neuritogenic determinant of bovine P2 protein in peripheral nerve myelin.

Experimental allergic neuritis (EAN) is an experimentally produced demyelinating disease of peripheral nervous system. Several peptides of bovine P2 protein were tested for neuritogenic activity in Lewis rats. The hexacosapeptide CiT4 (residues 53--78 of bovine P2 protein) showed the highest neuritogenic activity among the peptides tested.

The effects of d-nicotine and l-isomer on nicotinic receptors.

The effects of optically pure d-nicotine were investigated as compared with those of the l-isomer. d-Nicotine showed qualitatively the same effects as the l-isomer in the ganglionic or neuromuscular sites and the relative potency of the d-isomer was approximately 0.06 in the case of rat blood pressure (elevation), approximately 0.

Trigeminal nerve: the possible origin of substance p-nergic response in isolated rabbit iris sphincter muscle.

We determined the effects of trigeminal nerve denervation on the noncholinergic, nonadrenergic response to electrical transmural stimulation of the isolated rabbit iris sphincter muscle. The left ophthalmic nerve (first branch of the trigeminal nerve) was cut at the intracranial, peripheral site of the trigeminal ganglion and five to ten days later, the iris sphincter muscle isolated from the left eye (operated side) was found to produce a fast cholinergic contraction in response to electrical transmural stimulation and there was no evidence of noncholinergic, nonadrenergic contractions. On the other hand, in the iris sphincter muscle isolated from the right eye (control side), electrical transmural stimulation produced both cholinergic and noncholinergic, nonadrenergic contractile responses.

Effects of goniopora toxin on non-adrenergic, non-cholinergic response and purine nucleotide release in guinea-pig taenia coli.

1. Effects of goniopora toxin (GPT) on non-adrenergic, non-cholinergic inhibitory responses were examined in isolated guinea-pig taenia coli and the transmission mechanism was analysed.2.

Pharmacological characterization of the alpha adrenoceptors of the dog basilar artery.

The effects of alpha adrenoceptor agonists and antagonists on the postsynaptic alpha receptors were examined in the dog basilar, mesenteric and renal arteries and the type of alpha adrenoceptors present was characterized. In the basilar artery, noradrenaline, clonidine and phenylephrine produced almost the same maximal contraction, the pD2 values being 6.51 +/- 0.

Relationship between the effects of Goniopora toxin on action potential and on contractile force in guinea-pig papillary muscle.

Effects of Goniopora toxin (GPT) on cardiac action potential and on contractile force were investigated in isolated guinea-pig papillary muscle. GPT produced a positive inotropic effect by increasing contractile force and prolonging the relaxation time. The time-to-peak force was little affected.

Effects of 4-aminopyridine on the adrenergic nerve terminals of rabbit arteries.

Adrenergic nerves of the rabbit pulmonary artery and aorta were stimulated by electrical pulses (0.3 or 5 msec duration) and also by nicotine. The effects of 4-aminopyridine (4-AP), a potassium channel inhibitor, were investigated on contractile responses of these arteries or on 3H-efflux from [3H]norepinephrine-treated pulmonary artery in response to these stimuli.

Effects of guanabenz on the adrenergic mechanism in rabbit arterial strips.

Effects of guanabenz, a hypotensive agent, on the adrenergic mechanism were studied in isolated rabbit thoracic aorta and pulmonary artery and findings were compared with data obtained with clonidine and guanethidine. Guanabenz in concentrations higher than 10(-6) M produced weak contractions which were attenuated by phentolamine or yohimbine. Such concentrations of guanabenz competitively inhibited the contractile response to noradrenaline, but did not attenuate the response to tyramine.

Noncholinergic, nonadrenergic contraction and substance P in rabbit iris sphincter muscle.

In the rabbit iris sphincter muscle, electrical transmural stimulation produced fast and slow components of contraction which were markedly attenuated by tetrodotoxin. The fast component was augmented by physostigmine and was abolished by atropine, while the slow component was little affected. Adrenergic and ganglionic blocking agents did not inhibit the slow component.

[The sequential metabolic and histological changes occurring in dog leg muscles as a consequence of ischemia (author's transl)].

The present study was undertaken to investigate the sequential metabolic and histological changes occurring in dog leg muscles as a consequence of ischemia. The left hind limbs of 45 dogs were amputated at the middle of their thighs and after preserving them in ice water and room temperature for 6 and 12 hours, re-circulation was established. Observation was undertaken on 1) activity of muscle enzymes-CPK, GOT-m, and LDH in the venous blood from the re-circulated limbs, and 2) histological changes of muscles through light microscopy and electron microscopy.

Species and regional differences in cholinergic blocking actions of beta-bungarotoxin.

Effects of beta-bungarotoxin (beta-BuTX) on cholinergic transmission were examined in various tissues and species. In the guinea-pig atrial preparation, beta-BuTX in concentrations ranging from 0.01 to 10 microgram/ml abolished the negative inotropic and chronotropic responses to electrical stimulation of the vagus nerve.

Possible involvement of adenine nucleotides in sympathetic neuroeffector mechanisms of dog basilar artery.

The transmission mechanism of sympathetic neuroeffector was studied in the isolated dog basilar artery. Electrical transmural stimulation produced an initial contractile response which was followed by a transient relaxation or a late contraction, or both relaxation and contraction. These arteries showed a marked uptake of [3H]norepinephrine ([3H]NE) or [3H]adenosine after incubation with these compounds, and electrical stimulation increased the release of [3H]NE or 3H-purine compounds.

Effects of Goniopora toxin on guinea-pig blood vessels.

Effects of a marine polypeptide, Goniopora toxin (GPT) (molecular weight 12,000), were examined in isolated blood vessels guinea pigs. GPT, ranging from 10-100 nM, augmented the contractile response to electrical transmural stimulation in the thoracic aorta, portal vein, and mesenteric and femoral arteries. The effects were abolished by tetrodotoxin and bretylium, and were markedly attenuated by phentolamine.

beta-Bungarotoxin and parasympathetic nerve blocking action.

Autonomic effects of beta-bungarotoxin (beta-BuTX), a presynaptic blocking agent at the neuromuscular junction, were examined with parasympathetic (vagus), sympathetic nerve-atrial preparations isolated from guinea pigs. beta-BuTX in concentrations ranging from 0.01 to 10 micrograms/ml abolished the negative inotropic and chronotropic responses to electrical stimulation of the preganglionic trunks of the vagus nerve.

Reactivity of isolated canine cerebral arteries to adenine nucleotides and adenosine.

ATP (10(-8)-10(-5) M) produced phasic contraction in the canine basilar artery and relaxation in the middle cerebral artery. At high concentrations (10(-5) and 10(-4) M) a contractile response in the middle cerebral artery occasionally preceded relaxation. ADP, AMP, c-AMP and adenosine (10(-8)-10(-4) M) caused relaxation in all preparations except that ADP produced contraction in both cerebral arteries at high concentrations (10(-5) and 10(-4) M).