Maloy Mandal

Pouch colon associated with anorectal malformations fails to show spontaneous contractions but responds to acetylcholine and histamine in vitro

PURPOSE Congenital pouch colon (CPC) associated with anorectal malformation (ARM) is most commonly reported from Northern India. So far, no physiologic study comparing the detailed contractile status of CPC with non-CPC conditions are available. The present article deals with the contractile study and histopathologic observations in CPC, which may be useful for better surgical management. METHODS Freshly excised 12 neonatal CPC and similar number of non-CPC (control) specimens were transferred to ice-cold (4 degrees C-6 degrees C) Krebs-Ringer solution bubbled with 100% oxygen. Longitudinally prepared 2 to 4 colonic strips were obtained from central part of each specimen and subjected to the contraction recording after exposure to cumulative concentrations of acetylcholine (ACh) and histamine. Acetylcholine-induced contractions were evaluated after application of atropine (muscarinic blocker), and histaminergic contractions were recorded after pheniramine (H(1) blocker), lignocaine (neuronal blocker), and atropine. Histopathologic observations were made by using H&E and Masson trichrome stains. RESULTS Control specimens showed spontaneous contractions, but CPC strips did not. Both control and CPC responded to ACh and histamine. The response to histamine was greater (P < .05) in CPC as compared to control, whereas the response to ACh was more (P < .05) in control. In CPC, response of histamine (100 micromol/L) was blocked by pheniramine (0.32 mmol/L) and lignocaine (4 mmol/L) by 97% and 80%, respectively, and enhanced by 57% after preapplication of atropine (10 micromol/L). Acetylcholine (100 micromol/L)-induced contractions were attenuated (86%) in presence of atropine. Histopathologic examination showed fewer mature ganglion cells with various changes in muscle layers including fibrosis, disruption, hypertrophy, atrophy, and constriction bands. CONCLUSION Congenital pouch colon associated with ARM lacks normal spontaneous contractions but retains ACh and histamine-induced contractility. In view of the functional and histologic abnormalities, we propose that CPC associated with ARM is an abnormally functional and developed tissue. Therefore, resection of the pouch should be considered for better functional outcome of the remaining bowel.

Alterations of ventricular pH alter water intake and food consumption in rats

The pH of third ventricular CSF was altered by infusing acidic or alkaline solution of artificial cerebrospinal fluid (aCSF) through chronically implanted stainless steel cannula. In two separate group of rats (n = 18 each) water and food consumptions were recorded 30 min, 1 hr, and 24 hr after intraventricular infusions of the modified aCSF solutions having pH 6.0, 8.0 and 7.4 (control). On raising the CSF pH, water intake increased in all three observations. Feeding was not affected in the observations taken after 30 min and 1 hr, but significantly reduced food consumption was observed 24 hr after the infusions. Lowering of pH had no effect either on dipsogenic or feeding response. The CSF pH correlated positively with drinking in all three observations. Since dipsogenic and feeding responses are centrally regulated by ion sensitive cells, it may be presumed that altered CSF pH influenced the activities of the sensors by altering ionic conductance across their membranes.

Dipsogenic and feeding influences of intraventricularly infused anionic choline solutions.

Chloride and bicarbonate solutions of choline were infused into the anteroventral part of the third ventricle of two different groups of rats through chronically implanted stainless steel cannulae. Dipsogenic and feeding responses elicited by these solutions were studied by observations taken at half hour intervals up to two h and then, after 24 h of infusions. Results were compared with the control response evoked by similar infusion of artificial cerebrospinal fluid (aCSF). Food and water intakes were recorded in different groups (n = 18 each) of rats. Dipsogenic response elicited by choline chloride solution in the observation taken 24 h after infusion, however, was higher only as compared to the control. Dipsogenic effect of bicarbonate solution was not significantly different from the control in the first two observations (30 and 60 min), but in the later observations (90, 120 min and 24 h), it was significantly higher. None of the choline solutions significantly alter feeding response within 2 h of infusions. However, in the observation taken 24 h after infusion, the response evoked by choline chloride was greater than that elicited by aCSF. The results support our earlier observation that chloride concentration of third ventricular CSF significantly influences water and food consumption. Intraventricularly administered choline also appears to have positive influence on these behaviors.

A functional study on small intestinal smooth muscles in jejunal atresia

Aim: The present study was aimed to assess the contractile status of neonatal small intestinal smooth muscle of dilated pre-atretic part of intestinal atresia to resolve debatable issues related to mechanisms of persistent dysmotility after surgical repair. Materials and Methods: A total of 34 longitudinally sectioned strips were prepared from pre-atretic dilated part of freshly excised 8 jejunal atresia type III a cases. Spontaneous as well as acetylcholine- and histamine-induced contractions were recorded in vitro by using organ bath preparations. Chemically evoked contractions were further evaluated after application of atropine (muscarinic blocker), pheniramine (H1 blocker), and lignocaine (neuronal blocker) to ascertain receptors and neuronal involvement. Histological examinations of strips were made by using Masson trichrome stain to assess the fibrotic changes. Results: All 34 strips, except four showed spontaneous contractions with mean frequency and amplitude of 5.49 ± 0.26/min and 24.41 ± 5.26 g/g wet tissue respectively. The response to ACh was nearly twice as compared to histamine for equimolar concentrations (100 μM). ACh (100 μM) induced contractions were attenuated (by 60%) by atropine. Histamine (100 μM)-induced contractions was blocked by pheniramine (0.32 μM) and lignocaine (4 μM) by 74% and 78%, respectively. Histopathological examination showed varying degree of fibrotic changes in muscle layers. Conclusions: Pre-atretic dilated part of jejunal atresia retains functional activity but with definitive histopathologic abnormalities. It is suggested that excision of a length of pre-atretic part and early stimulation of peristalsis by locally acting cholinomimetic or H1 agonist may help in reducing postoperative motility problems in atresia patients.

Centrally infused anions alter body temperature in conscious rats

Central anionic influences on the regulation of body temperature were studied in 42 conscious male rats. The animals were divided into seven equal groups and were given intraventricular infusions of either chloride or bicarbonate solution of sodium, calcium, or potassium. Infusions were made in the unanesthetized and unrestrained animals through stainless steel cannulae, chronically implanted into the anteroventral part of third ventricle. Control rats received intraventricular infusions of artificial cerebrospinal fluid. All of the chloride solutions, irrespective of the associated cations, elicited hyperthermia, whereas bicarbonates had hypothermic effect. Responses of chloride and bicarbonate solutions varied significantly (p < 0.001). There was, however, cationic modification of the anionic responses. Thus, sodium ions manifested hyperthermic modifications, accentuating hyperthermia of chloride and attenuating hypothermic effect of bicarbonate. Calcium and potassium ions exerted hypothermic modulation. The results suggest that anionic concentration of intraventricular CSF is crucial for central regulation of body temperature in unanesthetized conscious rats. The cations probably have only modulatory influences.