摘要:

AbstractThe innervation of the duodenal enterochromaffine cells (E.C.) of the guinea pig was studied at the electronmicroscopic level. Pretreatment with 5‐OH‐dopamine was performed to visualize catecholaminergic (CA) nervous elements. Near the basement membrane of all examined E.C. in the crypts, bundles of unmyelinated nerve processes were observed, only partly ensheathed in a Schwann cell cover. At least 4 types of processes could be observed. 1) Boutons containing only small clear vesicles, probably cholinergic fibres; 2) boutons with small clear vesicles, and in addition large (200 nm) granules with a dense matrix (P‐type‐fibres); 3) boutons with small electron‐dense vesicles, probably CA‐fibres; and 4) processes with few vesicles but having the appearance of dendrites. No typical synaptic arrangements were observed, but the minimal distance between the E.C. and the nerve bundles was 150 to 250 nm, thus well within the functional limits of the “autonomic gap”. Thus, epithelial E.C. may be influenced by several types of nervous elements, incl

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06245.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractPulpal blood flow (PBF) was measured by H2‐gas clearance in 30 dogs during electrical nerve stimulation, denervation and close intraarterial infusion of noradrenaline (NA). Electrical stimulation of the cervical sympathetic nerve and NA infusion always resulted in decreased PBF. The constrictor effect was reduced by α‐blockers, but was never abolished or reversed to a vasodilation. Thus, no evidence for β‐receptors in the dental pulp blood vessels was found. The fall in PBF produced by cervical sympathetic stimulation could be prevented by cutting the inferior alveolar nerve in the mandibular canal. Stimulation of the cut inferior alveolar nerve in the mandibular canal produced variable pulpal flow changes: Both a marked increase and decrease were measured. The flow changes during inferior nerve stimulation were unaffected by α‐receptor blockade, while atropine reduced the vasoconstrictor respons or augmented the dilatory response. Electrical stimulation of the mandibular nerve before its entrance in the canal caused vasodilation, proposing a sensory antidromic axonreflex in the dental pulp. Sympathetic denervation had little or no effect on PBF, while cutting of the inferior alveolar nerve in the canal increased PBF in lower canine from 0.159 to 0.219 ml/min. g. The experiments show that pulp blood vessels of the dog may be controlled by both vasodilator and vasoconstrictor ne

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06246.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe sharpness of the frequency tuning of single auditory nerve fibers was studied in the rat on the basis of responses to broad band noise. The cross‐spectra between the sound stimulus and the sound‐to‐stimulus locked discharge rate were used as estimates of the transfer functions of the peripheral auditory analyzer. The sharpness of the tuning obtained in that way was measured as Q3dband Q10db It was found that these Q‐values decreased with increasing stimulus intensity but that the decrease was different when it was based on measurements at 3 dB points of the obtained transfer functions compared with measuring it at 10 dB points. The change in width was less for fibers with low CF. In all the fibers studied the frequency of maximal response (CF) decreased with increasing sound intensity. The implication of these findings for pitch perception and for noise induced hearing loss is di

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06247.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe nervous pathways between the small intestine of cat and guinea pig and various sympathetic ganglia were investigated by the retrograde horse‐radish peroxidase (HRP) technique. HRP was injected at multiple sites in the wall of the duodenum and the first third of the jejunum. At 1–5 days after (he injections. the HRP reaction product was searched for in various sympathetic ganglia. Not only the coeliac and nodose ganglia, but also the superior cervical, medial cervical, stellate and thoracic ganglia contained HRP‐positive nerve cells. Crushing the cervical vagal nerve prevented the occurrence of HRP‐reaction in the cervical ganglia, indicating that the HRP was transported from the gut to the cervical ganglia bia axons in the vagal nerve. The results demonstrate that the sympathetic ganglia in the neck (sup. and med. cerv. ganglia and stellate ggl.) send efferent fibres to the small in

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06248.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractIn an earlier study it was found that during paradoxical sleep (PS) thalamo‐cortical recruiting responses (RRs) and rapid eye movements usually did not appear simultaneously. As shown elsewhere, ponto‐geniculo‐occipital (PGO) wave activity and rapid eye movements are during PS closely related to each other in time. Similarly, in the present study it was observed that during paradoxical sleep in cats in which the center median nucleus of the thalamus was being stimulated at a rate of 7–9 Hz PGO waves in the geniculate nuclei did not in the rule occur in the presence of RRs recorded from the motor cortex. This effect was most pronounced with respect to series of PGO waves which usually occur at a rate of 4–7 Hz. On the basis of these experiments it was concluded that PGO waves and RRs are reciprocal events and mutually exclusive. Considering the well‐known fact that RRs represent synchronization. this negative correlation between RRs and PGO waves indicates that the desynchronizing tendency typical to paradoxical sleep is most pronounced during the occurrence o

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06249.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractBlood flow in the circumflex branch of the left coronary artery was recorded by electromagnetic flowmeter. In a group of dogs progressive hemodilution was performed until the diastolic reactive hyperemic response to 10 s occlusion of the circumflex branch disappeared (“optimum” hemodilution). At this degree of hemodilution the distribution of blood flow in the left ventricular free wall was evaluated by measuring tissue activity concentrations of Xe‐133 and radioactive microspheres after bolus injection into the aortic root. “Optimum” hernodilution was accompanied by a sixfold increase in systolic coronary flow, a 3‐fold increase in diastolic flow and a relative endocardial hypoperfusion. These results indicate that the endocardial blood flow reserve is lower than the epicardial. This conclusion is supported by the influence of spontaneous oscillations of arterial blood pressure (Traube‐Hering waves) on systolic and diastolic coronary blood flows before and during “optimum” hemodilution. In another group of dogs maximum coronary vasodilatation was produced by occlusion of the left coronary artery for 10 s. In this group the distribution of Xe‐133 and radioactive microspheres were measured after bolus injection into the aortic root at peak diastolic reactive hyperemia. The epi‐ and endocardial distribution of both Xe‐133 and microspheres was uniform in the left ventricular wall, indicating a uniform flow to these regions. This might be explained by an increased endocardial perfusion during systole due to loss of myocardial contractility or by a decline towards resting level in epicardial flow at the time of injection, corresponding to a shorter duration of the hyperemic period in the epi

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06250.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe effects of local heating on testicular and epididymal vascular resistance in sodium pentobarbitone anesthetized rats was measured with a microsphere technique. When exposing the left scrotum to 33 and 37°C for 30 min. no significant effects on blood flows were observed in comparison to those of the right side. Exposure to 41°C caused a significant (p<0.05) decrease in vascular resistance of both testes and epididymides. The response was more pronounced at 4°3. The Leydig cell function, as judged from the testosterone concentrations in plasma and testicular tissue after LH stimulation, was significantly (p<0.01) depressed at 41 and 43°C. It was concluded that the impaired Leydig cell function was unrelated to testicular blood f

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06251.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractCa uptake by microsomes isolated from non‐pregnant rabbit myometrium was potentiated by both inorganic phosphate (Pi) and oxalate anions. Both Piand oxalate bad little effect on the initial rate of uptake but a pronounced effect on the capacity of Ca uptake measured after 20 min which was greater in the presence of oxalate than that of Pi (5 mM each). The presence or absence of sucrose in the uptake medium had a significant effect on oxalate‐induced potentiation of Ca uptake but not on that potentiated by Pi or that measured in the absence of either potentiating anion. A part of Ca accumulated additionally under the influence of sucrose could be removed by washing microsomes with KCI.Another significant difference between the pontentiating effect of oxalate and Pi was observed when the pH of the incubation medium was varied. In the presence of oxalate the pH optimum was between 6.46.8, whereas that in its absence or in the presence of Pi the optimal pH was around 7.2. Reduction in pH from 7.2 to 6.8 along with the substitution of KCI by sucrose resulted in 3‐fold increase in Ca uptake when oxalate was used as the potentiating anion. The results suggest that Ca is taken up by a different mechanism in the presence of oxalate than that in its absence or when oxalate anion is substituted with inorganic phos

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06252.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe activity of certain enzymes of energy metabolism (cytochrome c oxidase, citrate synthase, malate dehydrogenase, and lactate dehydrogenase) and of lysosomes (β‐glucuronidase, β‐N‐acetylglucosaminidase, arylsuphatase, ribonuclease, deoxyribonuclease, acid phosphatase, and cathepsin D) was assayed fromm. rectus femorisof mice trained 5 days per week, 1 h per day for 4 weeks according to 4 different programmes: I. running speed 20 m/min, horizontal track, II. 25 m/min, horizontal track, III. 20 m/min 8° uphill inclination, and IV. 25 m/min 8° uphill inclination. Oxidative capacity increased and anaerobic capacity decreased without distinction between the different training programmes. Of acid hydrolases assayed the activities of β‐glucuronidase and cathepsin D were increased independently of training intensity. Simultaneous histochemical observations on β‐glucuronidase and arylsulphatase activities in the contralateral m. rectus femorisshowed more intense staining in red as compared to white muscle fibres. It is suggested that training affected the red fibres and that the applied level of loading was probably too low to cause major involvement

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06253.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe effects of the nonionic detergents Triton X‐45 and Triton X‐100 were studied in the frog muscle end‐plate, by intracellular recordings of spontaneous miniature end‐plate potentials (m.e.p.p.'s) and the potential changes produced by iontophoretic application of acetylcholine (ACh‐potentials). In addition, the ultra‐structural changes produced by Triton X‐100 were studied by transmission electron microscopic and freeze‐fracture techniques. It was found that Triton X‐45 and Triton X‐100 caused a rapidly developing reduction of the amplitude of the m.e.p.p.'s. The response lo iontophoretic application of acetylcholine was reduced by Triton X‐100. Following return to normal Ringer solution the ACh‐potentials recovered, although not completely. The dissociation constant calculated from the rate constants for onset and offset of the reaction (KD= k2/kl) was 5–50 μM depending on the type of stoichiometric reaction presumed to occur between Triton X‐100 and the cholinergic receptor. The ultrastructural changes observed indicate that the nerve terminal plasma membrane and mitochondria are affected by Triton X‐100. Leakage of Ca2+from the latter may therefore be the cause of the increase in m.e.p.p. frequency. It is concluded that the influence on the amplitude of the m.e.p.p.'s and the ACh‐potentials can be attributed to a direct effect of the detergent upon th

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06254.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY