Naloxone reversible reduction in brain monoamine synthesis following sciatic nerve stimulation

Brain monoaminergic neurons seem to be influenced by endogenous opioid systems as judged from largely indirect evidence. In an attempt to more directly study this interaction, we have analyzed the effect of sciatic nerve stimulation (rectangular pulses, frequency 3 Hz, pulse duration 0.2 msec, current intensity 6-20 times muscle twitch threshold) on the in vivo rate of tyrosine-and tryptophanhydroxylation, respectively, in the rat brain. This stimulation procedure has previously been shown to evoke naloxone reversible pain threshold elevation and a longlasting blood pressure reduction rats, with maximum reached about 1.5 h after stimulation. The formation of DOPA and 5-HTP in various parts of the central nervous system during 30 min after inhibition of L-amino-acid-decarboxylase by NSD 1015 was measured. Two hours after the sciatic nerve stimulation procedure a significant decrease in DOPA formation was obtained in the cerebral cortex and in the spinal cord. This effect was reversed by pretreatment with a high dose of naloxone (15 mg/kg s.c., 10 min before stimulation). A reduction in 5-HTP formation was also obtained in the cerebral cortex, with a concomitant reduction in tryptophan concentration. These effects appeared to be antagonized by naloxone treatment. In the spinal cord there was no change in the 5-HTP accumulation after stimulation, but an increase after stimulation plus naloxone pretreatment was obtained. These data infer that the activity of some central monoamine systems, such as the NA pathways originating in locus coeruleus can be reduced by physiological activation of endogenous opioid systems. This effect of the acupuncture like stimulation procedure may be related to clinically reported actions of acupuncture stimulation, which apart from pain relief include, for example, antagonism of heroin abstinence symptoms.

Long-lasting cardiovascular depression induced by acupuncture-like stimulation of the sciatic nerve in unanaesthetized spontaneously hypertensive rats

The influence of a prolonged low frequency electrical stimulation of the somatic afferents on cardiovascular and sympathetic nerve activities was investigated in unanaesthetized spontaneously hypertensive rats (SHRs) and Wistar-Kyoto normotensive rats (WKRs). In SHR, an elevation of blood pressure, heart rate and splanchnic nerve outflow was elicited during a 30-min period of sciatic nerve stimulation. Following the cessation of the stimulation, depressor response and bradycardia slowly developed and lasted up to 12 h. Activation of the group III or A-delta afferent fibers was essential for this post-stimulatory response. The progressive depressor response and a parallelled reduction of the splanchnic nerve activity, reached their maxima at about 1 h after the termination of the sciatic stimulation. The magnitude of the post-stimulatory depressor response was correlated with the prestimulatory control blood pressure level. There were also behavioural changes accompanying the depressor response. The cardiovascular and the behavioural depression were immediately reversed by naloxone (10-15 mg/kg, i.v.). The post-stimulatory depressor response was still present after bilateral sino-aortic denervation, but was absent in animals anaesthetized with chloralose and urethane. Emotional stress produced by air-blowing on the animal resulted in pressor response and tachycardia during the period of the stressful stimulation, but there was no depressor response following the termination of air-blowing. These findings indicate a sympathetic and cardiovascular depression induced by a prolonged stimulation of the somatic group III or A-delta afferent fibers; its long duration and naloxone reversibility suggest the involvement of endorphins in the mechanism of this response. The physiological significance of the effects of the prolonged somatic afferent stimulation and its possible relations with acupuncture are discussed.

Hypercapnia and hypoxia: chemoreceptor-mediated control of locus coeruleus neurons and splanchnic, sympathetic nerves

Utilizing single cell recording techniques to study brain norepinephrine (NE) neurons in the locus coeruleus (LC) and, in the same rats, registration of splanchnic nerve activity (SNA) the effects on these systems of hypercapnia and hypoxia, respectively, were studied. Hypercapnia (pCO2 36-103 mm Hg) caused a rapid increase in the firing rate of LC neurons as well as in SNA. This effect was directly correlated with the added amount of CO2 in the inspired gas mixture. This finding indicates a similar chemo-receptor-mediated regulation of LC neurons and SNA. Since deafferentation of peripheral chemoreceptors did not alter the response of these systems to hypercapnia, the chemoreceptors involved must be centrally located. In hypoxia (pO2 105-31 mm Hg) the overall effect on LC neurons was activation, whereas SNA was reduced. These effects were, however, not dose-dependent. Peripheral receptor deafferentation abolished the activation by hypoxia, suggesting that the LC neurons are influenced also by peripheral chemoreceptors. The results indicate that the previously observed increase in brain NE turnover in hypercapnia is largely secondary to increased neuronal activity and not due to, e.g., changes in metabolic enzymes. In addition, the data implicate chemoreceptors, centrally but also peripherally located, in the regulation of brain NE neurons in the LC. The activation of these neurons in hypercapnia, generally associated with increased apprehension in man, is consistent with the notion that the LC may serve as an alarm system in the brain.

Renal nerve activity and exaggerated natriuresis in conscious spontaneously hypertensive rats

Exaggerated natriuresis upon volume loading occurs in both human and animal hypertension and is mainly due to suppressed tubular reabsorption. To explore whether altered renal sympathetic activity contributes to this response, conscious male spontaneously hypertensive rats (SHR) were exposed to isotonic saline loading in comparison with normotensive male Wistar Kyoto rats (WKR). After a 60 min control hydropenic period, during which mean arterial pressure, heart rate, renal sympathetic nerve activity and urinary sodium excretion were followed, a 60 min period of intravenous volume expansion with isotonic saline (0.2 ml/min X 100 g b.w.) was started followed by a 60 min hydropenic recovery period. Already during the control period sodium excretion was significantly higher in SHR. During the volume load and subsequent recovery period a clearly exaggerated natriuresis occurred in SHR compared with WKR. Further, volume loading reduced renal sympathetic nerve activity in all animals, but significantly more in SHR. Moreover, volume loading reduced mean arterial pressure and heart rate in both groups. It is suggested that the accentuated reflex inhibition of renal sympathetic activity in SHR upon volume loading emanates from cardiac mechanoreceptors and partly explains the exaggerated natriuresis in SHR. This augmented "volume' reflex response is probably due to reduced systemic venous compliance in SHR with a consequently increased central filling and cardiac receptor activation.

Peripheral and central vascular compliances in conscious normotensive and spontaneously hypertensive rats

Changes of left atrial (LAP) and right atrial pressure (RAP) upon 10% and 20% blood volume expansion were studied in conscious spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKR) with intact nervous cardiovascular control. In a separate series the changes of central (CBV) and peripheral (PBV) blood volumes upon similar increases of total blood volume (TBV) were measured as well, throughout using male, adult SHR and WKR in both series. During volume expansion both LAP and RAP increased significantly more in SHR than in WKR, as did CBV, while PBV increased significantly less in SHR than in WKR. Total "effective' vascular compliance, defined as delta TBV/delta RAP, was significantly lower in SHR. From the two series of measurements central (CBV/LAP) and peripheral (PBV/RAP) vascular compliances could be separately deduced. Central vascular compliance was nearly 50% lower in SHR than in WKR. However, "unstressed' volume of the peripheral compartment appeared to be rather normal in SHR compared to WKR. It is therefore suggested that the decreased total vascular compliance seen in essential hypertension and in SHR is mainly due to a decreased distensibility of the systemic capacitance vessels.

An unusual case of localized multiple peptic ulcer of the gastric fundus producing a large exophytic fibrous pseudotumor

We report an unusual case of fundic ulcer of the stomach, suspected radiologically of being an intramural malignant tumor. Grossly the lesion was a protruding large fibrous pseudotumor, reminiscent of fibromatosis or of a granuloma with secondary ulceration. Microscopical examination revealed that it was an unusually voluminous fibrosis produced in the base of long-standing multiple peptic ulcers in a limited area of the gastric fundus. The fundic gland area is a rare site of peptic ulceration, and the occurrence of such an exophytic tumor-forming type of peptic ulcer in this area even rarer, only one relevant case having been reported before.

Endoscopic features of adenoma of the duodenal papilla in familial polyposis of the colon

The duodenal papillae of 24 patients with familial polyposis of the colon were examined in detail by duodenofiberscopy and endoscopic biopsy. Adenomas were detected in 12 of the 24 patients (50%). Endoscopically the duodenal papilla had a white nodular or granular surface in most of the patients in whom adenoma was detected. In two patients, however, the endoscopic picture of the adenoma at the duodenal papilla was almost normal. Based on these observations, endoscopy and biopsy of the duodenal papilla should be added to the usual examination done in patients with this disease.

Correlation between decreased heart rate and central inhibition of sympathetic discharge after prazosin administration in the spontaneously hypertensive rat

Mean arterial blood pressure, heart rate and splanchnic sympathetic discharge were recorded in conscious and anaesthetized spontaneously hypertensive rats (SHR). Administration of prazosin (1 mg/kg i.v.) reduced heart rate in most rats and this effect was closely parallelled by a decrease in sympathetic discharge. In contrast, administration of hydralazine (1 mg/kg i.v.) caused a sustained tachycardia and increased sympathetic nervous activity. The cardiovascular effects of prazosin (0.2-0.3, 1 and 3 mg/kg i.v.) were examined in different rat strains. Sprague-Dawley and Wistar-Kyoto rats responded with tachycardia whereas a significant bradycardia was observed in SHR following the higher doses of prazosin. It is suggested that the bradycardia obtained after prazosin administration is due to a central inhibition of sympathetic outflow, an effect possibly caused by blockade of alpha-adrenoreceptors. The different heart rate responses in different rat strains may be interpreted to reflect differences in sensitivity of central alpha-adrenoreceptors.

Distensibility of the left atrial wall in spontaneously hypertensive rats compared with that in normotensive Wistar-Kyoto rats

1. The cardiac mechanoreceptors, which in rats are mainly located in the left atrial wall, are reset in spontaneously hypertensive rats. The atrial pressure has to be almost twice as high in spontaneously hypertensive rats as in normotensive controls to produce similar receptors activations, as is apparent from previous studies. 2. The present study was performed to investigate whether this resetting is due to decreased distensibility of left atrial walls in the spontaneously hypertensive rats. 3. Static load-length relationships were investigated in vitro on left atrial strips, and pressure-volume relationships were studied on isolated left atria from spontaneously hypertensive and normotensive Wistar-Kyoto rats. 4. The force per cross-sectional area exerted during a relative length increase of 80% was significantly greater in spontaneously hypertensive rats. The dynamic but not in the static distensibility was significantly lower in these animals. 5. The decreased dynamic distensibility of left atrial walls in spontaneously hypertensive rats can at least partly explain the resetting of atrial receptor function.

Distensibility of left atrium in normotensive and spontaneously hypertensive rats

In spontaneously hypertensive rats (SHR) left atrial mechanoreceptors are reset. Thus, left atrial pressure must be almost twice as high in SHR as in normotensive rats to produce comparable degrees of receptor activation and reflex sympathetic inhibition. The present study was performed to investigate whether this resetting is due to a decreased atrial distensibility in SHR. Static load-length relationships were therefore investigated on isolated left atrial strips from 11 pairs of male SHR and Wistar Kyoto rats (WKR). After each experiment the strips were fixed at a passive tension of 4 mN and the average wall thickness was determined histologically. Furthermore, pressure-volume relationships were studied on non-beating, isolated left atria from SHR and WKR. Distensibility was here defined as % volume increase when LAP was increased from 2.5 to 12.5 mmHg either rapidly (0.5--1 s, "dynamic" distension) or slowly (3 min, "static" distension). Atrial wall thickness did not differ significantly in SHR and WKR, but the passive force (mN) per cross sectional area exerted during elongation above 80% was greater (P less than 0.05) in SHR. Also the "dynamic", but not the "static" volume distensibility was significantly lower in SHR (P less than 0.01). The decreased dynamic distensibility of SHR left atrial walls can at least partly explain the resetting of the atrial receptors activated during the rapid filling phase.

Spontaneous disappearance of fundic gland polyposis: report of three cases

Three cases are reported in which multiple sessile polyps of the stomach disappeared spontaneously during the follow-up period from 9 to 34 mo. All of the patients were middle-aged females, and the distribution of the polyps was limited to the portion of the stomach with fundic glands. Histolgoic examination revealed simple hyperplasia of the fundic glands with microcysts. The macroscopic and histologic pictures were the same as the gastric lesions ("fundic gland polyposis") found in cases with familial adenomatosis coli; however, colonic polyposis was not observed in our cases. The possible cause of the spontaneous disappearance of the polyps was discussed.

Diagnostic value of intraoperative fiberscopy for small-intestinal polyps in familial adenomatosis coli

X-ray examination and intraoperative fiberscopy of the small intestine were performed in 20 patients with familial adenomatosis coli. Roentgenographic study detected polypoid lesions in the upper jejunum in 2 patients (10%), and in the terminal ileum in 9 (45%). In contrast, endoscopic study revealed polyps in the jejunum in 10 patients (50%), and in the ileum in 14 (70%). Polyps in most cases were multiple and small in size (less than 3 mm in diameter). Histology revealed the lesions of the jejunum to be adenomas, and those of the ileum to be lymphoid hyperplasia with or without adenoma. The present study suggests that intraoperative endoscopy is much more valuable than roentgenography in detecting these minute polyps of the small intestine in this disease.

Turcot's syndrome and its mode of inheritance

Two sisters with Turcot's syndrome, in which malignant cerebral neoplasms are associated with colonic polyposis, are presented. Cases reported in the literature, including some familial cases, have also been analysed. In familial cases, sex was unrelated to the occurrence of this disease and it was found only among siblings of the same parents and not in other members of the family. There was consanguinity in the parents of the patients in two out of three families. We therefore concluded that the mode of inheritance in this condition is autosomal recessive and that it is genetically distinct from the ordinary form of familial polyposis coli. Support is lent to the absence of an association between the two disorders by a difference in the number, size, and distribution of the colonic polyps found in Turcot's syndrome as compared with familial polyposis coli.

Gastric lesions in familial adenomatosis coli: their incidence and histologic analysis

In order to detect accompanying gastric lesions, we examined 22 patients with familial adenomatosis of the colon belonging to 14 families. Various gastric lesions were confirmed in 15 patients (68.2 per cent) belonging to 13 families. The lesions were found histologically to be adenoma in nine cases, fundic gland polyposis in six, carcinoma in three, and microcarcinoid in two. Fundic gland polyposis consisting of simple hyperplasia of the fundic glands seems to be the gastric lesion specific to familial adenomatosis of the colon and rectum. Familial adenomatosis coli not only affects the colon and rectum, but is also capable of inducing tumorigenicity in other organs. The stomach is one of the organs in which extracolonic lesions occur.

An elderly case of mixed levocardia with situs inversus including inverted atria and complete transposition of the great vessels--an autopsied case

We reported on the autopsy of a 35-year-old man who had mixed levocardia with situs inversus including atrial inversion, transposition of the great vessels, and other complex cardiac malformations. Levocardia was discussed.

Small-intestinal involvement in familial polyposis diagnosed by operative intestinal fiberscopy: report of four cases

Operative intestinal fiberscopy, in which the duodenal fiberscope was introduced during laparotomy for colectomy in familial polyposis via the enterotomy opening, permitted the demonstration of small intestinal polyps in six of seven consecutive cases. Four of the six patients had adenomatous polyps in the proximal jejunum, including one patient with the concomitant presence of ileal adenomas. Polyposis due to lymphoid hyperplasia in the terminal ileum was found in three patients. Preoperative upper gastrointestinal surveys revealed adenomas in the duodenums of all seven patients, adenomas in the gastric antrum in three, and multiple hamartomas in the gastric corpus in two. Thus, in familial polyposis or Gardner's syndrome, more or less the entire gastrointestinal tract seems to be involved and the term "gastrointestinal polyposis" seems to describe these conditions.