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Subchronic preexposure to carbon monoxide modifies heart response to a combined CO + isoproterenol challenge in rats.
Gen Physiol Biophys. 1999 Oct; 18 Spec No:163-70.GP

Abstract

The effect of repeated exposure to carbon monoxide (CO) on the response of middle-age rats to an acute CO exposure combined with a low dose of a sympathomimetic agent was studied. A group of 12 rats (male albino, Wistar, age 9 months) without ECG abnormalities was divided into two subgroups matched for weight, heart rate and ECG: one subgroup was exposed to 500 ppm CO for 6 h/d, 5 d/w, for 6 weeks (peak COHb 31.5%, SD 3.5); the other one (controls) was exposed to fresh air. Two or three days after the last exposure both groups underwent combined challenge with 0.025 mg/kg isoproterenol s.c. and 90 minute exposure to CO in a concentration increasing from 500 to 1500 ppm; ECG was recorded continuously. The hearts were examined morphometrically and histologically. The CO-preexposed subgroup had, as compared to controls: 1) significantly higher blood hemoglobin (by 25%), erythrocyte count (by 28%) and volume (by 6%), and hematocrit (by 33%); 2) the same peak COHb; 3) lower basic heart rate and an earlier decrease after isoproterenol, 4) significantly smaller increase in ECG abnormalities and arrhythmias after isoproterenol and during CO exposure; 5) nonsignificantly higher heart weight indexes; 6) a nonsignificantly lower score of histological abnormalities. The global score of ECG pathology during CO exposure (abnormal pattern or arrhythmia) correlated best (multiple corr. coef. >0.9) with end-exposure free (non CO bound) hemoglobin (negatively) and with mean heart rate during exposure (positively): the lower score in the preexposed subgroup was attributable primarily to the increased hemoglobin. Six-week intermittent CO exposure induced marked compensatory processes (hematological) but only a tendency to adaptational changes in the heart (by gross morphometry), and decreased the ECG response to CO+ isoproterenol challenge at the same COHb.

Authors+Show Affiliations

Trávnícková Z
National Institute of Public Health, Prague, Czech Republic. ztravni@szu.cz
Frantík E
No affiliation info available
Blazek K
No affiliation info available
Janousek S
No affiliation info available

MeSH

AnimalsArrhythmias, CardiacCarbon MonoxideDrug InteractionsElectrocardiographyErythrocyte CountErythrocyte VolumeHeartHeart RateHematocritHemoglobinsIsoproterenolMaleRatsRats, Wistar

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

10703735

Citation

Trávnícková, Z, et al. "Subchronic Preexposure to Carbon Monoxide Modifies Heart Response to a Combined CO + Isoproterenol Challenge in Rats." General Physiology and Biophysics, vol. 18 Spec No, 1999, pp. 163-70.
Trávnícková Z, Frantík E, Blazek K, et al. Subchronic preexposure to carbon monoxide modifies heart response to a combined CO + isoproterenol challenge in rats. Gen Physiol Biophys. 1999;18 Spec No:163-70.
Trávnícková, Z., Frantík, E., Blazek, K., & Janousek, S. (1999). Subchronic preexposure to carbon monoxide modifies heart response to a combined CO + isoproterenol challenge in rats. General Physiology and Biophysics, 18 Spec No, 163-70.
Trávnícková Z, et al. Subchronic Preexposure to Carbon Monoxide Modifies Heart Response to a Combined CO + Isoproterenol Challenge in Rats. Gen Physiol Biophys. 1999;18 Spec No:163-70. PubMed PMID: 10703735.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Subchronic preexposure to carbon monoxide modifies heart response to a combined CO + isoproterenol challenge in rats. AU - Trávnícková,Z, AU - Frantík,E, AU - Blazek,K, AU - Janousek,S, PY - 2000/3/7/pubmed PY - 2000/4/1/medline PY - 2000/3/7/entrez SP - 163 EP - 70 JF - General physiology and biophysics JO - Gen Physiol Biophys VL - 18 Spec No N2 - The effect of repeated exposure to carbon monoxide (CO) on the response of middle-age rats to an acute CO exposure combined with a low dose of a sympathomimetic agent was studied. A group of 12 rats (male albino, Wistar, age 9 months) without ECG abnormalities was divided into two subgroups matched for weight, heart rate and ECG: one subgroup was exposed to 500 ppm CO for 6 h/d, 5 d/w, for 6 weeks (peak COHb 31.5%, SD 3.5); the other one (controls) was exposed to fresh air. Two or three days after the last exposure both groups underwent combined challenge with 0.025 mg/kg isoproterenol s.c. and 90 minute exposure to CO in a concentration increasing from 500 to 1500 ppm; ECG was recorded continuously. The hearts were examined morphometrically and histologically. The CO-preexposed subgroup had, as compared to controls: 1) significantly higher blood hemoglobin (by 25%), erythrocyte count (by 28%) and volume (by 6%), and hematocrit (by 33%); 2) the same peak COHb; 3) lower basic heart rate and an earlier decrease after isoproterenol, 4) significantly smaller increase in ECG abnormalities and arrhythmias after isoproterenol and during CO exposure; 5) nonsignificantly higher heart weight indexes; 6) a nonsignificantly lower score of histological abnormalities. The global score of ECG pathology during CO exposure (abnormal pattern or arrhythmia) correlated best (multiple corr. coef. >0.9) with end-exposure free (non CO bound) hemoglobin (negatively) and with mean heart rate during exposure (positively): the lower score in the preexposed subgroup was attributable primarily to the increased hemoglobin. Six-week intermittent CO exposure induced marked compensatory processes (hematological) but only a tendency to adaptational changes in the heart (by gross morphometry), and decreased the ECG response to CO+ isoproterenol challenge at the same COHb. SN - 0231-5882 UR - https://www.unboundmedicine.com/medline/citation/10703735/Subchronic_preexposure_to_carbon_monoxide_modifies_heart_response_to_a_combined_CO_+_isoproterenol_challenge_in_rats_ DB - PRIME DP - Unbound Medicine ER -