The Contribution of cocoa additive to cigarette smoking addiction

More documents

Recommendations

Info

Page 72 of 207 RIVM report 650270002 Histamine unclear, but it is suggested that this receptor belongs to the superfamily of G-proteincoupled receptors (14). Pulmonary system breathing frequency: In spontaneously breathing dogs, the inhalation of histamine caused an increased respiratory frequency, decreased tidal volume, and decreased dynamic lung compliance (17). However, some conflicting results were obtained about the breathing frequency in humans after histamine inhalation. In one study the breathing frequency remained unchanged after histamine inhalation in both nonsmokers and smokers (18). In another study the effects of inhalation of histamine on respiratory frequency (fR) were evaluated in 63 humans. Forty four subjects were hyperresponsive (BHR+). In each of these subjects, the doses of histamine applied for the present study (mean 3.5 mg/ml) caused a decrease in forced expiratory volume in one second (FEV1) that was greater than 20% of the control value. The dose of histamine applied in the 19 nonhyperresponsive subjects (BHR-) was substantially larger (8.0 mg/ml) whilst for this dose the decrease in FEV1 was less than 20% of control value. After histamine, fR was significantly increased in both subgroups of subjects, BHR+ and BHR-. In general, the changes in fR were not uniform; 40 subjects responded with an increase and 23 with a decrease (19). tidal volume: The respiratory response to bronchospasms induced by histamine inhalation was measured in nonsmokers and asymptomatic smokers. In each subject, tidal volume (VT) and inspiratory time (TI) were measured. The respiratory responses to histamine were the same in both groups: the tidal volume (VT) increased and the inspiratory time (TI) remained unchanged. Thus, VT/TI, an index of respiratory drive also increased (18). In another study, the effects of inhalation of histamine on respiratory frequency (fR), tidal volume (VT), minute ventilation (V'E), and functional residual capacity (FRC) were evaluated in 63 humans. Forty four subjects were hyperresponsive (BHR+). In each of these subjects, the doses of histamine applied for the present study (mean 3.5 mg/ml) caused a decrease in forced expiratory volume in one second (FEV1) that was greater than 20% of the control value. The dose of histamine applied in the 19 nonhyperresponsive subjects (BHR-) was substantially larger (8.0 mg/ml) whilst for this dose the decrease in FEV1 was less than 20% of control value. After histamine, fR was significantly increased in both subgroups of subjects, BHR+ and BHR-. The increase in V'E was significant in BHR- but not significant in BHR+. In general, the changes in V'E, fR and VT were not uniform; comparable numbers of subjects responded with increases (n=33) and decreases (n=30) in V'E. For fR 40 subjects responded with an increase and 23 with a decrease, and for VT these numbers were 26 and 37, respectively. The increase in FRC after histamine application was significantly larger in BHR+ subjects than in BHR-. These findings may be interpreted to indicate that different mechanisms with opposite effects may be operating simultaneously, e.g. excitation of central inspiratory activity by stimulation of rapidly-adapting pulmonary stretch receptors, which will promote increases in respiratory frequency, tidal volume and minute ventilation, and bronchoconstriction with increased airway resistance, which will promote decreases in these parameters. As a consequence, depending on the net result of these opposite contributions to, e.g. minute ventilation, administration of
RIVM report 650270002 Page 73 of 207 Histamine histamine will cause an increase in minute ventilation in one subject and a decrease in another (19). Both hypercapnic (n = 7) and normocapnic (n = 6) patients with chronic obstructive pulmonary disease were exposed to doubling concentrations of aerosolized histamine, and FEV1 was measured 30 and 90 s after each 2-min exposure. A provocative dose (PD20) of histamine was defined as that which produced a 20% decrease in FEV1. At PD20, minute ventilation and tidal volume (VT) decreased in both groups. The decrease in VT was significantly greater in the normocapnic patients. Inspiratory flow (VT/TI) did not change in either group (20) (the dosage is not mentioned in the abstract). lung compliance: In spontaneously breathing dogs, the inhalation of histamine caused a decreased dynamic lung compliance (17) (the dosage is not mentioned in the abstract). airway resistance: The airway resistance is increased by histamine. Histamine inhalation dose causing a 20% fall in forced expiratory volume in one second (PD20) has been described by several studies. It was shown in young normal adults that the optimal cut-off point for PD20 was 0.73 mg (21). Another study found a mean histamine PD20 dose of 1.20 mg in young normal adults. In asthmatics the histamine PD20 dose was 0.23 mg (22). In 6 subjects in whom dose-response curves were obtained for mass of histamine deposited in the lungs and the FEV1, the mean deposited histamine mass required to decrease the FEV1 by 10% was 0.11 mg (23). Cardiovascular system Histamine is stored in large amounts in human cardiac tissue, where it is contained in cytoplasmatic granules of mast cells (24). Histamine content in human heart tissue was found to be 1.7 ± 0.1 µg/g wet weight (mean ± standard error on the mean). Spontaneous release of histamine from heart tissue is negligible. The local concentration of histamine appears to be high enough to play some role in the modulation of several cardiac functions in vivo (25). blood pressure: Histamine characteristically causes dilatation of the finer blood vessels, resulting in flushing, lowered total peripheral resistance and a fall in systemic blood pressure. In addition histamine tends to increase capillary permeability. Its effects on the heart are generally less important. The vasodilatation involves both H1 and H2-receptors, distributed throughout the resistance vessels in most vascular beds. Activation of H1-receptors mediates a dilatation that is relatively rapid in onset and short-lived. Activation of H2receptors mediates a dilatation that develops more slowly and is more sustained (13). Intracerebroventricularly (i.c.v.) injection of histamine in rat produced a prompt dose-dependent (0.01 – 11µg/dose ) and long-lasting (1-11 µg/dose) increase in mean arterial pressure (MAP), pulse pressure (PP) and heart rate (HR). It was concluded that histamine H2 receptors were involved in the histamine induced central cardiovascular effects (26). Experiments have been made in anaesthetised cats and dogs and in healthy, human volunteers to compare the changes in blood
Page 1 and 2:
RIVM report 650270002/2002 The cont
Page 3 and 4:
RIVM report 650270002 Page 3 of 207
Page 5 and 6:
Page 7 and 8:
Page 9 and 10:
Page 11 and 12:
Page 13 and 14:
Page 15 and 16:
Page 17 and 18:
Page 19 and 20:
Page 21 and 22: RIVM report 650270002 Page 21 of 20
Page 47 and 48: Page 47 of 207 RIVM report 65027000
Page 71: RIVM report 650270002 Page 71 of 20
Page 123 and 124:
Page 125 and 126:
Page 125 of 207 RIVM report 6502700
Page 127 and 128:
Page 129 and 130:
Page 131 and 132:
Page 133 and 134:
Page 135 and 136:
Page 137 and 138:
Page 139 and 140:
Page 141 and 142:
Page 143 and 144:
Page 145 and 146:
Page 147 and 148:
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
Page 155 and 156:
Page 157 and 158:
Page 159 and 160:
Page 161 and 162:
Page 163 and 164:
Page 165 and 166:
Page 167 and 168:
Page 169 and 170:
Page 171 and 172:
Page 173 and 174:
Page 175 and 176:
Page 177 and 178:
Page 179 and 180:
Page 181 and 182:
Page 183 and 184:
Page 185 and 186:
Page 187 and 188:
Page 189 and 190:
Page 191 and 192:
Page 193 and 194:
Page 195 and 196:
Page 197 and 198:
Page 199 and 200:
Page 201 and 202:
Page 203 and 204:
Page 205 and 206:
Page 207:
show all

The Contribution of cocoa additive to cigarette smoking addiction

Create successful ePaper yourself

Delete template?

Save as template?