摘要:

AbstractIntradental sensory nerve impulse activity was recorded by means of electrodes inserted into dentinal cavities In the tooth of the cat. Impulses of different amplitudes was recorded. Local application of aconitine (10‐3g/ml) and veratrine (10‐3g/ml) induced nerve impulse activity. A rapid increase in the temperature of the tooth surface to 45–47°C, which is known to induce fluid, movements in the dentinal tubuli, did not induce any nerve impulse activity. However, after pretreatment of a tooth cavity with veratrine a rapid increase in the temperature of the tooth surface gave rise to nerve impulse activity. Steady state impulse activity induced by brief local application of aconitine was influenced by a rapid increase in the temperature of the tooth; during the increase in temperature impulses of low amplitude increased in frequency while impulses of high amplitude were blocked. Furthermore, reduced pressure applied to the exposed dentin, which also induces fluid movements in the dentin, gave rise to nerve impulse activity. Thus the sensory units in the tooth are stimulated by dentinal fluid movements and alkaloids known to excite mechanoreceptors increase their excitability. It is therefore suggested that the intradental sensory nerve endings are mechanosensitive stru

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1976.tb10295.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractAdult non‐cold adapted rats were injected with 6‐hydroxydopamine (6‐OHDA) or saline and their interscapular brown adipose tissue (BAT) was removed after appropriate periods of time. Fluorescence histo‐chemistry of control BAT demonstrated the presence of an extensive network of varicose fibers among the adipocytes and at the blood vessels. This was confirmed by electron microscopy which a!so revealed large and small dense core vesicles sparsely distributed in axons and terminals indicating the presence of noradren‐aline (NA). After 6‐OHDA injection the fluorescence from varicosities was abolished both among the adipocytes and at the vessels. Thus, chemical sympathectomy was more effective than surgical‐ or immuno‐sympathectomy, which spare the innervation of adipocytes. Parallelling the disappearance of fluorescence was a significant decrease of measurable NA. During recovery the extractable NA increased before the reappearance of fluorescent varicosities. This could be explained by transmitter accumulation in the nerve‐trunks within the tissue, which, in general, appeared unaffected by 6‐OHDA. A large number of cells with a strong yellowish fluorescence distributed through the BAT was unaffected by 6‐OHDA. There was no evidence for the presence

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1976.tb10296.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractOn male Sprague Dawley rats isotonic NaCl during control and 1 M NaCl were infused either into the carotid artery or i.v. Glomerular filtration rate, sodium output and plasma renin activity were determined. Five of 19 animals reacted with no increase in sodium output for 1 M NaCl and are treated as a different group from the animals reacting with an increased sodium output. For the animals reacting with an increased sodium output a decrease in plasma renin activity was found together with an increase in glomerular filtration rate. In both groups the plasma sodium was constant. The animals not reacting with an increased sodium output had a higher initial plasma renin activity, which did not change during 1 M NaCl infusion. The responses were equal for both intracarotid and i.v. infusions but with a somewhat longer delay before the response occurred with i.v. infusions. These results might be explained by a central nervous effect and by a direct renal effect. Also during 1 M NaCl infusion a possible extracellular volume expansion, derived from water withdrawal from the cells into the extracellular space might occur.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1976.tb10297.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractAn investigation was made of the effect of adrenaline on the tissue level and release of cyclic AMP (CAMP) into the incubation medium by the isolated rat diaphragm preparation. Adrenaline, added in vitro, caused a dose‐dependent biphasic increase in the tissue level of the nucleotide. A significant elevation of the level of cAMP in the tissue was observed throughout a 60 min incubation period in the presence of 0.01, 0.1 and 10μg/ml of adrenaline. The hormone also produced a small but significant increase in the release of cAMP into the incubation medium. The accumulation of cAMP in the incubation medium ceased after 10 min of incubation in the presence of adrenaline, although the tissue level of the nucleotide remained considerably elevated throughout the entire incubation period. Theophylline potentiated the effect of adrenaline on both the accumulation of cAMP in the tissue and in the incubation medium. Theophylline by itself also increased the tissue level of cAMP slightly. It is concluded from the present study that the elimination of cAMP from the rat diaphragm muscle by release of the nucleotide from the cells is sma

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1976.tb10298.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractPrevious studies on intact human subcutaneous tissue have shown, that blood flow remains constant during minor changes in perfusion pressure. This so‐called auto regulatory response has not been demonstrable in isolated preparations of adipose tissue. In the present study on isolated, denervated subcutaneous tissue in female rabbits only 2 of 12 expts. revealed an auto regulatory response duringreductionin arterial perfusion pressure. Effluent blood flow from the tissue in the control state was 15.5 ml/100 g·min (S.D. 6.4, n = 12) corresponding to slight vasodilatation of the exposed tissue. Following total ischemia all experiments showed a period with reactive hyperemia, and both duration of hyperemia and excess flow was related to the duration of the ischemia. This response therefore seems more resistant to the experimental procedure, while auto regulation of blood flow to lowered pressure is more susceptible to surgical exposure of the tissue.Duringelevationof arterial perfusion pressure blood flow in the isolated tissue showed a transient increase and then almost returned to the level during normotension, indicating an elevated vascular resistance. Raising of venous pressure elicited vasoconstriction with pronounced flow reduction. These two reactions may be important for local regulation of blood flow in subcutaneous tissue during orthostatic changes in arterial and venous pressure. It is concluded that the response in adipose tissue to changes in arterial pressure (auto regulation), venous pressure and total ischemia appear to be elicited by different mechanis

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1976.tb10299.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractIncreased transmural pressure in the pulmonary arterial bed may reduce vascular input impedance and reduce hydraulic power linked to pulsatile blood flow. Vascular impedance and pulsatile hydraulic power (Wp) levels of isolated perfused rabbit lungs were compared after similar rises of pulmonary arterial pressure (PAp), induced either by vasoconstriction or by left atrial pressure (LAp) elevation. Resulting Wp levels were significantly smaller after vasoconstriction than LAp elevation. Wp showed a minimum level at physiologic PAp (about 20 cm H2O) irrespective of the cause of PAp elevation. Pressure pulse wave reflection coefficient (Γ) was calculated for control and test situations, and was found to be approximately doubled after vasoconstriction. Only minor changes in Γ were found after LAP elevation. Accordingly, moderate vasoconstriction (resulting PAp≅20 cm H2O) caused a backward traveling pressure wave of high amplitude, appearing in counter‐phase to the forward pressure wave at the input site. The total pressure wave amplitude was thereby markedly lowered, resulting in a reduced Wp level. We assume that this effect of moderate vasoconstriction may be one reason for the existence of vascular smooth muscles in the pulmonary art

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1976.tb10300.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThis study was designed to evaluate the influence of sympathetic nerve stimulation (NS) and α‐adrenergic receptor stimulation (αS) on the pulmonary vascular input impedance and hydraulic power output of the right heart during variations of cardiac output (CO). An open chest cat preparation was used and pulsatile pressure and flow in the pulmonary artery were measured by high frequency response transducers. Calculations showed that vascular resistance (VR) was inversely dependent on CO, hut input impedance of the unstimulated lung was not influenced by CO variations. NS or αS increased VR and input impedance significantly, and the relation pulsatile hydraulic power/total hydraulic power (Wp/Wt) increased 40%, indicating that such stimulation has larger relative influence on impedance than on resistance. The reduction of arterial compliance during NS (maximal stimulus) was calculated to be 60%, independent of CO. Input impedance during NS or αS was reduced by CO elevations, probably because the concomitant distension of the arterial bed reduced arterial resistance and inertance. The ratio Wp/CO, which expresses the fraction of pulsatile hydraulic power lost per ml mean arterial flow, was found to be flow dependent both in control and stimulated conditions: Wp/CO was positively correlated to CO in control condition and weakly negatively correlated to CO during stimulation. At high CO the arterial vessels could he stimulated and stiffened without much extra load on the right

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1976.tb10301.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractA computer model of the pulmonary arterial (PA) bed of rabbit lungs was designed in order to test experimental observations of changes in PA input impedance and pulsatile hydraulic power (cap.) during increased PA pressure. The computer model was based on a simple 3‐component analog representation of single vessels (i.e. resistance, inertance and compliance). 16 generations of arterial vessels, from PA to 60 μm diameter, were combined to calculate PA input impedance. Input impedance was found to mimic closely that observed experimentally. Both venous pressure elevation and arteriolar constriction was found to reduce input impedance and Wp. By combining arteriolar constriction with increased myogenic tone of the larger arteries, Wp was found to show a minimum level at a certain PA pressure, dependent on the degree of arterial stiffening. Wp was found to follow changes in arterial volume and resistance during simulated vasoconstriction. Wp dissipation in arterial vessels was calculated to approx. 50% of total input Wp at physiological pressure conditions, and could be reduced by one half after PA pressure increase from 20 to 50 cm H2O, despite a concurrent halving of arterial compliance. Arterial vessels smaller than 200pmdiameter were found to have negligible direct influence on PA input impedan

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1976.tb10302.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractA Mg2+‐ and Ca2+‐dependent ATPase at the outer surface of human peripheral lymphocytes and hematopoietic cell lines has been studied. The enzyme activity varied about 60 fold between the extremes of the cell lines tested. There was no simple relationship between surface‐ATPase activity and cell surface area. Nor was the presence of villi or any other morphological characteristic at the cell surface decisive for the degree of surface‐ATPase activity. A correlation was, however, found between the ATPase activity and a phenomenon probably involving a contractile process namely immunoglohulin secretion, but it was not possible to establish an interdependence of these cell characte

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1976.tb10303.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractHypercapnic acidosis (pH 7.0) inhibits the lipolytic response of canine subcutaneous adipose tissue to i.v. infused noradrenaline (NA) by 80 per cent or more. The response to sympathetic nerve stimulation, on the other hand, is only reduced by 1040 per cent during acidosis. The fate of intravenously infused3H‐labelled NA (0.35 ug × kg‐1× min‐1for 30 min) was not significantly altered by acidosis. The rate of disappearance of unmetabolized NA from the arterial plasma after an infusion was the same at pH 7.4 and 7.0 and the calculated increase in circulating NA during infusions was 4 ng/ml at both pH:s. I.v. infusion of Na increases adipose tissue blood flow, an effect which is attenuated by acidosis. There was a significant correlation (p<0.001) between adipose tissue blood flow and the lipolytic response at normal pH. Preventing the NA‐induced increase in blood flow by constant flow perfusion reduced the lipolytic response at normal pH. The degree of inhibition by acidosis of the lipolytic response to i.v. NA was significantly reduced (from 79 to 56 per cent, p<0.05) when the adipose tissue was perfused at constant flow. These data suggest that adipose tissue blood flow is important in determining the lipolytic response to i.v. NA, probably by influencing the delivery of NA to the tissue. The marked inhibition by acidosis of lipolysis due to i.v. infused NA therefore appears to be the combined effect of a direct antilipolytic effect of acidosis and a decreased delivery of N A to the adipose tissue due to the attenuated blood flow

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1976.tb10304.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY