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J Németh

Publications and source records attributed to J Németh.

At least 37 records · Page 2Linked to original sources
PubMed1999

Impairment of neurogenic inflammatory and anti-inflammatory responses in diabetic rats.

The effect was studied of a primary (preconditioning) neurogenic inflammatory challenge induced by electrical stimulation of the peripheral stump of the sciatic nerve (20 V, 0.5 ms, 5 Hz, for 5 min) on neurogenic oedema (5 min later) induced by stimulation of the contralateral sciatic nerve. Plasma extravasation due to the second stimulation was decreased by 52.7+/-3.1% (P<0.01) in normal animals and by 29.7+/-2.2 and 18.1+/-1.5% with 50 mg/kg streptozotocin pretreatment i.v. 4 and 8 weeks previously, respectively. Subsequently, bilateral sciatic nerve stimulation increased baseline plasma somatostatin levels from 6.4+/-0.3, 11. 7+/-1.4, and 16.8+/-3.8 to 28.3+/-2.9 (P<0.01), 17.9+/-3.7, and 25. 1+/-1.7 pmol/l in normal, and 4- and 8-week diabetic animals, respectively. We conclude that experimental diabetes impairs the capability of a preconditioning neurogenic inflammatory episode to elicit a systemic anti-inflammatory effect. This is accompanied by a deficiency in elevation of the plasma somatostatin level in response to nerve stimulation, although the baseline plasma somatostatin level increases proportionally to the duration of experimental diabetes.

Animals↗
PubMed1999

Endothelin release by capsaicin in isolated working rat heart.

Capsaicin (1 nM-1 microM) induced a concentration-dependent decrease in heart rate, coronary flow, aortic flow, left ventricular developed pressure and its first derivative, dP/dt(max) in isolated working rat heart. The effect of 10 nM capsaicin was mimicked by 0.1 nM endothelin. PD142893 (200 nM), a non-selective endothelin receptor blocking agent antagonized the effect of either endothelin (0.1 nM) or capsaicin (10 nM). We conclude that the majority of the effects of capsaicin in the rat heart are mediated by neural endothelin release.

Animals↗
PubMed1999

[Results of photorefractive keratectomy after treatment of 2053 eyes].

To evaluate the 12 months refractive results of photorefractive excimer keratectomy (PRK) in high number of eyes with different type of refractive error. Between October 1992 and December 1996. 2053 eyes of 1098 patients were treated with the Aesculap Meditec MEL 60 argon-fluoride excimer laser. Refractive results were concluded at the 12th post-PRK month. The following patient groups were used during the study: Group 1.: Eyes between -1.0 D and -6.0 D (n = 651); Group 2.: -6.0 és -9.0 D (n = 216); Group 3.: Eyes with refractive error above -9.0 D (n = 163); Group 4.: Hypermetrop eyes (n = 160); Group 5.: Eyes with myopic astigmatism (n = 746); Group 6.: Eyes with hypermetropic astigmatism; Group 7.: Pure astigmatism (n = 13). In Group 1. The preoperative average -3.94 +/- 1.3 D refractive error decreased during the 1-year follow-up period to -0.47 +/- 0.54 Dpt; in Group 2. The preoperative -7.65 +/- 1.07 D to -1.16 +/- 1.86 D; in Group 3. The preoperative average -13.58 +/- 3.51 D to -3.11 +/- 2.75 D; in Group 4. The preoperative +4.04 +/- 1.77 D to +1.02 +/- 1.16 D in Group 5. The preoperative -6.06 +/- 2.78 D spherical component decreased to -0.95 +/- 1.33 D-ra, whereas the preoperative cylindrical component from -1.5 +/- 1.08 D to -0.13 +/- 0.58 D; in Group 5. The preoperative +4.57 +/- 1.78 spherical component to +1.13 +/- 1.38 D; whereas the preoperative cylindrical component from +1.57 +/- 0.96 D to +0.38 +/- 0.77 D; in Group 7. The preoperative a -3.98 +/- 1.2 D cylinder decreased to -0.62 +/- 0.75 D cylinder. PRK decreased effectively the preoperative correction need in every treatment group. The results are the better, the smaller the preoperative correction need is.

Adolescent↗
PubMed1999

Capsaicin-insensitive sensory-efferent meningeal vasodilatation evoked by electrical stimulation of trigeminal nerve fibres in the rat.

1. Antidromic vasodilatation and plasma extravasation to stimulation of the trigeminal ganglion or its perivascular meningeal fibres was investigated by laser-Doppler flowmetry and 125I-labelled bovin serum albumin in the dura mater and in exteroceptive areas (nasal mucosa, upper eyelid) of anaesthetized rats pretreated with guanethidine and pipecuronium. 2 Trigeminal stimulation at 5 Hz for 20 s elicited unilateral phasic vasodilatation in the dura and lasting response in the nasal mucosa. Resiniferatoxin (1-3 microg kg(-1) i.v.), topical (1%) or systemic capsaicin pretreatment (300 mg kg(-1) s.c. plus 1 mg kg(-1) i.v.) did not inhibit the meningeal responses but abolished or strongly inhibited the nasal responses. Administration of vinpocetine (3 mg kg(-1) i.v.) increased both basal blood flow and the dural vasodilatation to perivascular nerve stimulation. 3. Dural vasodilatation to trigeminal stimulation was not inhibited by the calcitonin gene-related peptide-1 receptor (CGRP-1) antagonist hCGRP8-37 (15 or 50 microg kg(-1) i.v), or the neurokinin-1 receptor antagonist RP 67580 (0.1 mg kg(-1) i.v.) although both antagonists inhibited the nasal response. Neither mucosal nor meningeal responses were inhibited by atropine (5 mg kg(-1) i.v.), hexamethonium (10 mg kg(-1) i.v.) or the vasoactive intestinal polypeptide (VIP) antagonist (p-chloro-D-Phe6-Leul7)VIP (20 microg kg(-1) i.v.). 4. Plasma extravasation in the dura and upper eyelid elicited by electrical stimulation of the trigeminal ganglion was almost completely abolished in rats pretreated with resiniferatoxin (3 microg kg(-1) i.v.). 5. It is concluded that in the rat meningeal vasodilatation evoked by stimulation of trigeminal fibres is mediated by capsaicin-insensitive primary afferents, while plasma extravasation in the dura and upper eyelid and the vasodilatation in the nasal mucosa are mediated by capsaicin-sensitive trigeminal fibres.

Animals↗
PubMed1999

[Exit of the retinal central vascular trunk and extent of para-papillary atrophy].

PURPOSE: To evaluate whether the position of the central retinal vessel trunk exit on the lamina cribrosa spatially correlates with the location of parapapillary atrophy in glaucoma. METHODS: Color stereo optic disc photographs of 79 patients with primary or secondary open-angle glaucoma and 53 normal subjects were morphometrically evaluated. We determined the position of the central retinal vessel trunk exit on the lamina cribrosa surface and measured the area of parapapillary atrophy in four 90 degrees quadrants. RESULTS: After correction for normal values, the beta zone area of parapapillary atrophy in the glaucoma eyes was significantly larger, when measured in the disc quadrant most distant to the central retinal vessel trunk exit than as if measured in the quadrant containing the vessel trunk exit. CONCLUSIONS: Position of the central retinal vessel trunk exit on the lamina cribrosa influences the location of parapapillary atrophy in glaucoma. The longer the distance to the central retinal vessel trunk exit, the more enlarged is parapapillary atrophy.

Adult↗
PubMed1999

Effect of a liquid meal given as a bolus into the jejunum on human pancreatic secretion.

Major features of pancreatic secretion stimulated by a meal depend on intestinal phase mechanisms. However, an intrajejunal (i.j.) meal infusion is widely used for the treatment of inflammatory pancreatic diseases when the resting of the gland is desired. This study was undertaken to compare the effects of an intragastric (i.g.) and an i.j. complete fluid (Lundh) test meal on pancreatic enzyme secretion. Eight men (mean age, 43 years; range, 31-48) free from pancreatic disease were studied. Pancreatic secretion was measured via a multiple-lumen tube by aspiration of the duodenal juice. After a fasting period, the Lundh test meal was placed in the stomach or the upper jejunum. After the i.g. administration of the test meal, the aspirated duodenal juice was reinfused into the jejunum. The effect of atropine infusion (0.5 microg/kg/h) on the pancreatic enzyme secretion was studied. The pancreatic amylase, trypsin, and lipase outputs were determined. The plasma levels of cholecystokinin (CCK) and of gastrin were measured by bioassay and radioimmunoassay, respectively. The trypsin, amylase, and lipase secretions increased significantly after either an i.g. or an i.j. test meal intake. The trypsin, amylase, and lipase outputs were significantly decreased during the i.j. perfusion as compared with i.g. administration. The gastrin levels increased significantly after i.g., but remained unchanged after i.j. administration. The CCK release attained its maximum 40 and 60 min after the i.g. and i.j. test meal, respectively. However, the CCK release was significantly lower during the i.j. administration as compared with i.g. perfusion. An atropine infusion significantly reduced the i.g. and i.j. test meal-stimulated enzyme outputs. An i.j.-administered meal stimulates the pancreatic enzyme secretion, but this effect is significantly lower than that which occurs on i.g. administration. The i.j. meal-stimulated secretion of pancreatic enzymes is subject to both cholinergic and peptidergic regulation. The deficiency of gastrin and the delayed and decreased CCK release are believed to account for the reduced enzyme output.

Adult↗
PubMed1999

Substance P radioimmunoassay for quantitative characterization of sensory neurotransmitter release.

In the present work we report the development of a new radioimmunoassay method for measuring the substance P content liberated from isolated rat tracheae in response to electrical or chemical (capsaicin, resiniferatoxin, piperine) stimulation. The amount of substance P released by electrical stimulation has been found to be dependent on the number of pulses and chemically elicited substance P release also proved to be dose-dependent. Our findings reinforce previous data that resiniferatoxin is approximately 100 times more potent than capsaicin and the potency ratio between piperine and capsaicin is 1/50.

Alkaloids↗
PubMed1998

[Closure of the patent ductus arteriosus by means of cardiac catheterization].

Authors report their results with transcatheter closure of patent arterial duct during a period of 1 year. Thirty patients underwent the procedure at the mean age of 5.22 yrs (range 5 mos-22.3 yrs) and mean bodyweight of 19.1 kg (range 5.8-73 kg). There were 9 males and 21 females. The diagnosis of the patent arterial duct was established by physical examination and noninvasive techniques. The procedures were attempted in all patients above 5 kg bodyweight with patent arterial duct and normal pulmonary artery pressure, irrespective of the shunt-size. All procedures were performed under general anesthesia in one session with the diagnostic cardiac catheterisation. Transcatheter closure was successful in 29 patients. In one patient the device embolized into the left pulmonary artery, snaring was unsuccessful, surgical closure of the patent duct and removal of the device took place uneventfully. Control aortography 15 minutes after the coil placement showed insignificant residual shunt through the patent duct in 8 patients (27%), while echocardiography at 1 month proved complete closure in all. The patients were followed by noninvasive methods. No mortality was observed. Authors emphasize the low risk and cost-effectiveness of the procedure. They stress the importance of the patients selection. Authors applied the technique for the first time and introduced it to the regular patient-care practice in Hungary.

Adolescent↗
PubMed1998

Inhibition of nociceptin on sensory neuropeptide release and mast cell-mediated plasma extravasation in rats.

Nociceptin (20 microg/kg i.p.) strongly inhibited cutaneous Evans blue accumulation in the chronically denervated hindpaw of the rat in response to mast cell degranulating peptide (MCDP, 0.25 microg in 100 microl) but it had no and marginal effect on plasma extravasation induced by 5-hydroxytryptamine (5-HT, 0.5 microg in 100 microl) and histamine (0.1 microg in 100 microl), respectively. Release of sensory neuropeptides such as substance P, calcitonin gene-related peptide (CGRP) and somatostatin from the rat isolated trachea in response to capsaicin (10(-8) M) or bradykinin (10(-7) M) were also attenuated by nociceptin (100 and 300 nM). It is concluded that chemically induced discharge of mediators from mast cells and from capsaicin-sensitive afferent nerve terminals are both inhibited by nociceptin that participates in the anti-inflammatory effect of the peptide.

Animals↗
PubMed1998

Excimer laser treatment of hyperopia.

PURPOSE: The aim of this study was to analyse the clinical results of hyperopic photorefractive keratectomy treatments and to compare the results achieved with the usage of different masks. METHOD: 20 eyes of 16 hyperopic patients were treated, using the Aesculap-Meditec MEL60 193nm ArF excimer laser. The mean duration of follow-up was 9.9+/-3.4 months. Statistical comparison of the results with the two masks was made using the unpaired Student t-test. RESULTS: Preoperative mean spherical equivalent was +4.23+/-1.18D, which changed to +0.20+/-0.78D at one month and regressed to +1.23+/-1.27D at the last control examination. After 6 months 60% (12 eyes) had spherical equivalent within +/-1.0D of the attempted correction. The statistical analysis showed no significant difference between the results with the two masks. CONCLUSION: Good preparation for the treatment is of equal importance for the results of the photorefractive keratectomy as compared to the technical circumstances.

Adult↗
PubMed1998

Release of somatostatin and its role in the mediation of the anti-inflammatory effect induced by antidromic stimulation of sensory fibres of rat sciatic nerve.

1. The effect of antidromic stimulation of the sensory fibres of the sciatic nerve on inflammatory plasma extravasation in various tissues and on cutaneous vasodilatation elicited in distant parts of the body was investigated in rats pretreated with guanethidine (8 mg kg(-1), i.p.) and pipecuronium (200 microg kg(-1), i.v.). 2. Antidromic sciatic nerve stimulation with C-fibre strength (20 V, 0.5 ms) at 5 Hz for 5 min elicited neurogenic inflammation in the innervated area and inhibited by 50.3 +/- 4.67% the development of a subsequent plasma extravasation in response to similar stimulation of the contralateral sciatic nerve. Stimulation at 0.5 Hz for 1 h also evoked local plasma extravasation and inhibited the carrageenin-induced (1%, 100 microl s.c.) cutaneous inflammation by 38.5 +/- 10.0% in the contralateral paw. Excitation at 0.1 Hz for 4 h elicited no local plasma extravasation in the stimulated hindleg but still reduced the carrageenin-induced oedema by 52.1 +/- 9.7% in the paw on the contralateral side. 3. Plasma extravasation in the knee joint in response to carrageenin (2%, 200 microl intra-articular injection) was diminished by 46.1 +/- 12.69% and 40.9 +/- 4.93% when the sciatic nerve was stimulated in the contralateral leg at 0.5 Hz for 1 h or 0.1 Hz for 4 h, respectively. 4. Stimulation of the peripheral stump of the left vagal nerve (20 V, 1 ms, 8 Hz, 10 min) elicited plasma extravasation in the trachea, oesophagus and mediastinal connective tissue in rats pretreated with atropine (2 mg kg(-1), i.v.), guanethidine (8 mg kg(-1), i.p.) and pipecuronium (200 microg kg(-1), i.v.). These responses were inhibited by 37.8 +/- 5.1%, 49.7 +/- 9.9% and 37.6 +/- 4.2%, respectively by antidromic sciatic nerve excitation (5 Hz, 5 min) applied 5 min earlier. 5. Pretreatment with polyclonal somatostatin antiserum (0.5 ml/rat, i.v.) or the selective somatostatin depleting agent cysteamine (280 mg kg(-1), s.c.) prevented the anti-inflammatory effect of sciatic nerve stimulation (5 Hz, 5 min) on a subsequent neurogenic plasma extravasation of the contralateral paw skin. The inhibitory effect of antidromic sciatic nerve excitation on plasma extravasation in response to vagal nerve stimulation was also prevented by somatostatin antiserum pretreatment. 6. Cutaneous blood flow assessment by laser Doppler flowmetry indicated that antidromic vasodilatation induced by sciatic nerve stimulation was not inhibited by excitation of the sciatic nerve of the contralateral leg (1 Hz, 30 min) or by somatostatin (10 microg/rat, i.v.) injection. 7. Plasma levels of somatostatin increased more than 4 fold after stimulation of both sciatic nerves (5 Hz, 5 min) but the stimulus-evoked increase was not observed in cysteamine (280 mg kg(-1), s.c.) pretreated rats. 8. These results suggest that somatostatin released from the activated sensory nerve terminals mediates the systemic anti-inflammatory effect evoked by stimulating the peripheral stump of the sciatic nerve.

Animals↗
PubMed1998

Systemic anti-inflammatory effect induced by counter-irritation through a local release of somatostatin from nociceptors.

1. Neurogenic plasma extravasation evoked by topical application of 1% vv(-1) mustard oil on the skin of the acutely denervated rat hindleg (primary reaction) inhibited the development of a subsequent oil-induced plasma extravasation induced in the skin of the contralateral hindleg by 49.3+/-7.06% (n=9) and in the conjunctival mucosa due to 0.1% wv(-1) capsaicin instillation by 33.5+/-10.05% (n=6). The primary reaction also inhibited the non-neurogenic hindpaw oedema evoked by s.c. injection of 5% wv(-1) dextran into the chronically denervated hindpaw by 48.0+/-4.6% (n= 5). 2. Capsaicin injection (100 microg ml(-1) in 50 microl, s.c.) into the acutely denervated hindleg caused 56.5+/-4.0% (n=5) inhibition in the intensity of plasma extravasation elicited by 1% vv(-1) mustard oil smearing on the contralateral side. After chronic denervation, subplantar injection of 5% wv(-1) dextran elicited a non-neurogenic inflammatory response with intensive tissue oedema without causing any systemic anti-inflammatory effect. Bilateral adrenalectomy did not inhibit the mustard oil-induced anti-inflammatory effect in the contralateral hindleg. 3. Pretreating the rats with polyclonal somatostatin antiserum (0.5 ml rat(-1), i.v.) or with the somatostatin depleting agent cysteamine (280 mg kg(-1), s.c.) prevented the inhibitory action of mustard oil-induced inflammation on subsequent neurogenic plasma extravasation and strongly diminished the inhibition of non-neurogenic oedema formation evoked by dextran. 4. Exogenous somatostatin (10 microg kg(-1), i.p.) caused a 30.3+/-8.3% (n=6) inhibition of plasma extravasation caused by mustard oil smearing on the acutely denervated hindleg and this inhibitory effect was abolished by somatostatin antiserum (0.5 ml rat(-1), i.v.). The plasma level of somatostatin-like immunoreactivity (SST-LI) increased by 40.03+/-6.8% (n= 6) 10 min after topical application of 1% vv(-1) mustard oil on the acutely denervated hindpaws compared to the paraffin oil treated control group. Chronic denervation of the hindlegs or cysteamine (280 mg kg(-1), s.c.) pretreatment prevented the mustard oil-induced elevation of SST-LI in plasma. 5. It is concluded that chemical excitation of the capsaicin-sensitive sensory receptors not only induces local neurogenic plasma extravasation but also inhibits the development of a subsequent inflammatory reaction at remote sites of the body in the rat. A role for somatostatin in this systemic anti-inflammatory effect is suggested.

Animals↗
PubMed1998

[Experiences with the rectal use of a chemotherapeutic agent. 1. In vitro biopharmaceutical examinations; selection of the optimal vehicle].

The factors influencing in vitro liberation (Part 1) and in vivo absorption (Part 2) from trimethoprim-containing rectal suppositories and the authors' results related to them are reported in this two-part publication. Special emphasis was laid on selecting the optimal suppository base which is harmless physiologically yet not indifferent pharmacologically. From among the 24 compositions studied, a lipophilic mixture containing a surface active additive (Witepsol W 35) and a hydrophilic (Macrogolum) mixture were found to be the best in all respects. Liberation from the trimethoprim-containing rectal suppositories was measured with in vitro dynamic diffusion and spectrophotometrically. A power relation was found to exist between the quantity of the released pharmacon and the diffusion time, and a significant negative exponential relation was observed between the doses and their respective in vitro availability values.

Administration, Rectal↗
PubMed1998

[Experiences with the rectal use of chemotherapeutic agents. 2. Pharmacokinetic examinations with animals].

The aim of the investigations was to optimise vehicle for trimethoprim (TMP) suppositories ready for clinical trials. The rectal absorption of TMP was studied in anaesthetized rats. The drug liberation properties of the five mixed vehicles with promising in vitro results (Part 1.) were studied. The course of the blood level curves was monitored with serial sampling. The TMP concentration of blood was determined by bioassay. Individual bases were compared with the use of the pharmacokinetic parameters derived from the analysis of the obtained blood level curves, with special respect to biological availability (BA). The extent of bioavailability is influenced considerably by the hydro-, lipo- or lipohydrophilic property of the vehicle. TMP, if incorporated in the proper vehicle, is absorbed well. With three vehicles the extent of absorption exceeded the absorption seen with oral administration on the same model (BA = 38.8%). The best results were achieved with the lipophilic base Witepsol W 35 containing 10% of Polysorbate 20 and 10% of Polysorbate 61 (BA = 63.8%) and with Witepsol W 35 containing 10% of Polysorbate 60 (BA = 64.9%). The hydrophilic Macrogol 1540 vehicle containing 5% of Macrogol 400 had only slightly worse results (BA = 52.9%). In the case of the lipohydrophilic Witepsol W 35 vehicle with 10% of Polysorbate 20 and 10% of Polysorbate 61 content a significant negative exponential relation was found between the administered doses and their respective bioavailability values, this tendency had been observed during the in vitro examinations, too. No such relation was found in the case of the lipophilic Witepsol W 35 vehicle containing 10% of Miglyol 812.

Administration, Oral↗
PubMed1997

[Urinary calcium excretion. (Normal values for urinary calcium/creatinine ratio in Hungary). Multicenter study].

Metabolic bone disorders have attracted increasing attention in Hungary due to their significant impact on public health care. Measuring urinary calcium excretion is the first step in the biochemical assessment of bone metabolism. Fasting urinary calcium corrected by creatinine excretion is widely used all over the world. The aim of the present study was to establish standard methods and normal values for the calcium/creatinine ratio in Hungary. Twenty-four centers specializing in metabolic bone diseases participated in the study. Urine standards were sent out to these centers for calcium and creatine determinations. Based on the collected data, methods were corrected in order to achieve similar results for the standards. In the second phase of the study, the normal values for calcium/creatinine ratio were determined in SI units based on the data from 1846 healthy subjects (age 20-80 yrs) including 944 females and 902 males. The normal value for females was 0.438 +/- 0.391 (means +/- SD), and 0.395 +/- 0.352 for males, respectively (p < 0.03). The ratio increased with age in both sexes. The highest values were observed between 60-64 years in women and 70-74 years in men, respectively. After this peak, the calcium/creatinine ratio decreased. The values before and after 45 years of age were significantly different both in women (0.37 +/- 0.36, vs. 0.52 +/- 0.41, p < 0.001; and men (0.32 +/- 0.23, vs. 0.47 +/- 0.45, p < 0.001). The use of this distinction is recommended in the everyday practice.

Adult↗
PubMed1997

Capsaicin-sensitive local sensory innervation is involved in pacing-induced preconditioning in rat hearts: role of nitric oxide and CGRP?

UNLABELLED: Among several mediators, nitric oxide (NO) and calcitonin gene-related peptide (CGRP) were suggested to be involved in the mechanism of preconditioning. We examined the possible role of the cardiac capsaicin-sensitive sensory innervation in pacing-induced preconditioning, as well as in the cardiac NO and CGRP content. Wistar rats were treated subcutaneously with capsaicin or its solvent in the sequence of 10, 30, and 50 mg/kg increasing single daily doses for 3 days to deplete neurotransmitters of the sensory innervation. Isolated hearts from both groups were then subjected to either preconditioning induced by three consecutive periods of pacing at 600 beats per minute for 5 min with 5 min interpacing periods, or time-matched non-preconditioning perfusion, followed by a 10-min coronary occlusion. NO content of left ventricular tissue samples was assayed by electron-spin resonance, and CGRP release was determined by radioimmunoassay. CGRP immunohistochemistry was also performed. In the non-preconditioned, solvent-treated group, coronary occlusion decreased cardiac output (CO) from 68.1 to 32.1 mL/min, increased left ventricular end-diastolic pressure (LVEDP) from 0.58 to 1.90 kPa, and resulted in 200 mU/min/g LDH release. Preconditioning significantly increased ischaemic CO to 42.9 mL/min (P < 0.05), decreased ischaemic LVEDP to 1.26 kPa (P < 0.05) and decreased LDH release to 47 mU/min/g (P < 0.05) in the solvent-treated group. Preconditioning did not confer protection in the capsaicin-pretreated group (ischaemic CO: 35.6 mL/min; LVEDP: 1.76 kPa; LDH 156 mU/min/g). Capsaicin-treatment markedly decreased cardiac NO content, CGRP release, and CGRP-immunoreactivity. CONCLUSIONS: (i) The presence of an intact local sensory innervation is a prerequisite to elicit pacing-induced preconditioning in the rat heart. (ii) A significant portion of cardiac basal NO content may be of neural origin. (iii) Release of NO and CGRP from capsaicin-sensitive nerves may be involved in the mechanism of pacing-induced preconditioning.

Animals↗
PubMed1997

Acute myocardial infarction enhances the portal venous histamine level in dogs.

OBJECTIVE AND DESIGN: The aim of our experiments was to determine the plasma histamine level in the portal venous (VP) blood during acute coronary occlusion and reperfusion. SUBJECTS: 27 adult mongrel dogs of either sex were randomized for three groups: sham-operated controls, occlusion group (group O) and reperfusion group (group R). TREATMENT: The left circumflex coronary artery (LCx) was proximally occluded and the occlusion was maintained during 6 h (group O), or after a 60-min occlusion the LCx was reperfused (group R). The portal vein was cannulated to take blood samples for hormone measurements. METHODS: The plasma histamine concentrations were measured with the radioenzymatic method. RESULTS: The VP plasma histamine level was significantly increased 60 min after the LCx occlusion in groups O (99.9 +/- 40.2 vs. 252.9 +/- 100 pg/ml, mean +/- SD) and R (101.2 +/- 55.1 vs. 179.8 +/- 96 pg/ml), and remained high in group O (240.4 +/- 81 pg/ml), while 2 h after LCx reperfusion it had decreased to the basic level. There was no correlation between the hemodynamic parameters and the portal vein plasma histamine levels. CONCLUSIONS: Histamine is released into the gastrointestinal tract during acute myocardial ischemia and reperfusion, but the release of the vasoactive drug has no effect on systemic hemodynamics.

Animals↗