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PubMed1996

Evaluation of colchicine with or without praziquantel therapy in the control of hepatic fibrosis in murine schistosomiasis.

Colchicine alone or following praziquantel was given to mice infected with Schistosoma mansoni either 6 or 10 weeks post infection. Praziquantel increased body weight gain, histologically reduced number, diameter and cellularity of granuloma and improved liver function parameters. Early praziquantel therapy decreased hepatic collagen content as detected by the colorimetric method and the serum procollagen propeptide (PIIIP), while later treatment at the 10th week of infection increased hepatic collagen content and serum PIIIP. Colchicine therapy significantly decreased body weight gain with significant weight loss after early treatment. Colchicine did not change the histologic picture of schistosomal liver fibrosis; it induced a detectable hepatocytic injury recorded ultrastructurally and histologically with excitation of the inflammatory reaction in the granuloma and in portal tracts after early treatment. Excess pigmentation in macrophages and Kupffer cells, binucleation and large sized hepatocytic nuclei were evident after colchicine therapy. Colchicine increased hepatic collagen content microgram/mg protein, raised globulin and total serum protein and normalized the raised serum PIIIP of infected mice, but had no effect on PIIIP of normal mice. Early cessation of schistosomal infection evidently minimized the adverse effects of colchicine.

Animals↗

PubMed1997

Colchicine does not ameliorate bleomycin-induced pulmonary injury in hamsters.

We have evaluated the effect of colchicine, a potential antifibrotic drug, on bleomycin-induced pulmonary inflammation in hamsters. Pulmonary injury was induced by a single intratracheal (IT) instillation of bleomycin (bleo). Four groups of male Syrian hamsters each received one of four treatments: (1) IT bleo and twice daily intraperitoneal (IP) injections of colchicine (col) starting one day before IT instillation of bleo (bleo-col); (2) IT bleo and IP injections of saline (bleo-sal); (3) IT saline and IP colchicine (sal-col); and (4) IT saline and IP saline (sal-sal). Animals were sacrificed 28 days after IT treatment. Lung injury was evaluated histologically, biochemically and by analysis of bronchoalveolar lavage (BAL) fluid. Treatment of hamsters with colchicine did not ameliorate the bleo-induced lung injury, as determined by a semiquantitative morphological index that assesses the severity and extent of the lung injury on a scale of 0-3. Lung hydroxyproline measurements and BAL fluid cell count were also similar in bleo-col compared to bleo-sal hamsters. Colchicine did not prevent the bleo-induced restriction expressed by volume displacement. These results indicate that colchicine does not ameliorate the bleo-induced lung inflammation and fibrosis and call for further controlled investigations to justify the use of this drug in pulmonary disorders.

Animals↗

PubMed1999

ATP-Dependent colchicine transport by human erythrocyte glutathione conjugate transporter.

We have recently demonstrated mutually inhibitory ATP-dependent transport of dinitrophenyl-S-glutathione (DNP-SG) and doxorubicin by DNP-SG ATPase purified from human erythrocyte membranes (S. Awasthi et al., 1998a,b). Our previous studies indicate a broad substrate specificity for this transport mechanism, including some P-glycoprotein substrates. Present studies were carried out to determine whether colchicine (COL), a classical P-glycoprotein substrate, could be transported by purified human erythrocyte DNP-SG ATPase reconstituted in artificial liposomes. We also investigated whether leukotriene C4 (LTC4), an endogenous proinflammatory glutathione-conjugate derived from arachidonic acid, would inhibit colchicine transport. Uptake of COL was compared in proteoliposomes reconstituted with the purified DNP-SG ATPase as well as control liposomes in the presence or absence of ATP. Increased colchicine uptake was observed upon addition of ATP to proteoliposomes, but not control liposomes. Uptake was linear with respect to the amount of vesicle protein used. Sensitivity to osmolarity was consistent with intravesicular COL accumulation. The ATP-dependent colchicine uptake was sensitive to temperature in a manner consistent with a protein-mediated transport process with activation energy of 7.3 kcal/mol. Time-dependent COL uptake by proteoliposomes in the presence of ATP was consistent with a single compartment model with an apparent rate constant of 0.21 +/- 0.02 min-1. Kinetic studies indicated a saturable behavior with respect to ATP (Km 2.3 +/- 0.7 mM) and colchicine (Km 4.3 +/- 0.2 microM). LTC4 was found to be a competitive inhibitor of COL transport (Kis 16.4 microM). Since DNP-SG ATPase is present in many tissues, it may play an important role in determining colchicine accumulation in cells. Increased LTC4 would tend to increase cellular COL accumulation.

Adenosine Triphosphatases↗

PubMed1978

Effects of colchicine on ultrastructure of the lactating mammary cell: membrane involvement and stress on the Golgi apparatus.

The effects of colchicine on ultrastructure of the lactating mammary cell in the rat and goat were studied by electron microscopy. Changes in tissue of the rat were examined over time (1, 2 and 4 h). The goat gland was evaluated by comparing ultrastructure of tissue at the time of maximum milk flow suppression induced by the drug with that of untreated tissue. Colchicine produced notable changes in the tissue of both species: 1) the secretion of lipid droplets and Golgi vesicle contents (exocytosis) was inhibited and the droplets and vesicles became randomly distributed throughout the cell, 2) the Golgi apparatus was significantly reduced in size, 3) casein and lipid continued to be synthesized as evidenced by greater numbers of secretory vesicles and increased sizes of casein micelles and lipid droplets, 4) secretory vesicles showed a propensity to cluster around lipid droplets, 5) isolated microtubules were found occasionally in the control tissue, ordinarily in the vicinity of the Golgi apparatus, but rarely in the colchicine-treated tissue. These observations indicate that colchicine has two effects leading to suppression of exocytosis in the mammary cell: one involves early interference with capacity of secretory vesicle membranes to fuse and a further effect, related to higher concentrations of colchicine, causes intracellular disorganization and loss of polarity. Microtubules were not seen as directly involved in the mechanisms of exocytosis. The secretion of milk fat globules is coupled to exocytosis and thereby is also inhibited by colchicine.

Animals↗

PubMed1981

Inhibition of glycoconjugate secretion by colchicine and cytochalasin B. An in vitro study of human airway.

The effects have been analyzed of cytochalasin B and colchicine on the secretion of glycoconjugates by human bronchial explants labeled in vitro with radioactive glucosamine. Both cytochalasin B and colchicine had no effect on baseline 14C-labeled glycoconjugate release but caused a dose-dependent (10(-7)-10(-4) M) inhibition of 14C-glycoconjugate release and discharge of labeled macromolecules from mucous and serous cells induced by 5 X 10(-5) M methacholine. Quantitative autoradiographic analyses showed that neither cytochalasin B nor colchicine inhibited 3H-threonine or 3H-glucosamine incorporation into mucous and serous cells of the submucosal glands or goblet cells of the airway epithelium. Colchicine (10(-5) M) but not cytochalasin B significantly reduced the rate at which labeled macromolecules were transported through mucous, serous and goblet cells but this effect was not observed until 4h after the addition of colchicine. Neither cytochalasin B nor colchicine affected the basal rate of labeled-macromolecule discharge from mucous, serous or goblet cells. At a concentration of 10(-5) M, both agents completely inhibited the increase in labeled-macromolecule discharge induced in mucous and serous cells by methacholine. Our results suggest that in the submucosal gland of human airways microtubules and microfilaments may be important in secretagogue-induced but not in baseline cellular glycoconjugate discharge, implying that the mechanisms of the two processes differ significantly. Furthermore, a role for microtubules is suggested in the transport of secretory granules through mucous, serous and goblet cells.

Aged↗

PubMed1985

Effects of neonatal intraocular colchicine on synaptogenesis and on the retention of the ipsilateral retinofugal projection within the superior colliculus.

A normally transient ipsilateral retinofugal projection exists in the rat but is retained following eye removal because of the loss of competitive interaction between crossed and uncrossed fibers. To further explore this phenomenon, colchicine (10(-3)M) was injected into the right eye of newborn albino rats to partially suppress axonal transport in optic fibers, alter the developmental time course of retinofugal synaptic terminals and determine if this would in turn extend the period of survival of the ipsilateral projection. Measurements of the number of fibers in the nerve were also made to insure that colchicine was not lethal to the retinofugal projection. Projections into the superior colliculus were demonstrated by anterograde movement of HRP from the left eye. TMB histochemistry revealed dense labeling of the contralateral retino-recipient layers at 5 dpn in untreated or saline-injected controls. The ipsilateral projection was seen as a lighter band of activity across the colliculus which was most concentrated in the antero-medial quadrant. This pathway was transient and degenerated by 10 dpn, except for a few antero-medial fibers. Animals treated with colchicine demonstrated a retention of this pathway through 20 dpn. A concomitant quantitative analysis of synaptic development within the superior colliculus revealed populations of boutons with round (R) and flattened (F) vesicles, as well as multiple junctional (MJ) and serial (S) complexes, most of which were specialized R boutons. The various synaptic categories displayed specific ratios unique to the different stages of maturation. Intraocular colchicine reduced the ratio of R, MJ and S boutons to F terminals between 5-15 dpn (P less than 0.01). By 20 dpn, the proportions of MJ and S boutons remained depressed but the normal ratio of R to F boutons was restored. Areal determinations of each synaptic profile included in the counts revealed a significant reduction in the size of MJ synaptic profiles examined in colchicine-treated animals and this may have been reflected in the slight loss of tectal volume (6-9%). Removal of the left eye and assessment of degenerating boutons showed that the expanded ipsilateral projection was not sufficiently dense to produce such a restoration. It thus appears that colchicine delayed the growth of the R population, but the effect was reversible and this category of boutons continued to develop, albeit on a later time course.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1993

Effect of cyclosporine on colchicine partitioning in the rat liver.

Colchicine is secreted into bile as a major pathway of elimination. Cyclosporine (CsA) inhibits colchicine biliary secretion. In the present study, the effects of cyclosporine and its vehicle (cremophor) on the partitioning of colchicine across the liver were studied. CsA decreased the colchicine bile/plasma ratio from 484 +/- 39 to 53 +/- 3 (P < 0.001). This effect was due to both a decrease in bile/liver partitioning (control, 35.1 +/- 1.2, vs CsA treatment, 9.2 +/- 0.5; p < 0.001) as well as a decrease in liver/plasma partitioning (control, 13.7 +/- 0.8, vs CsA treatment, 5.7 +/- 0.4; P < 0.001). Cremophor also decreased the colchicine bile/plasma ratio (317 +/- 19, P < 0.02 vs control), but this effect was due to a decrease in the liver/plasma ratio (9.99 +/- 0.7, P < 0.02 vs control) rather than the bile/liver ratio (31.9 +/- 2.1, P > 0.2 vs control). Inhibition at the canalicular membrane is consistent with the location of gp-170, the presumed transporter of colchicine.

Analysis of Variance↗

PubMed1987

Effects of colchicine on the hepatocellular transport of indocyanine green in the rat.

The effects of colchicine on plasma elimination and biliary excretion of indocyanine green (ICG) and sulfobromophthalein (BSP) in rats were examined. Elimination of two different doses of ICG (6 mg and 20 mg/kg body weight) from plasma was significantly delayed when rats were treated with colchicine (3 mg/kg body weight) 3 h prior to the administration of the dye. On the other hand, disappearance of BSP (100 mg/kg) from plasma was not influenced by colchicine. The fact that the difference in the ICG elimination from plasma between colchicine-treated and saline-treated rats was minimal in the early period (i.e., 2 min after administration of the dye), but evident after its half-life (i.e., 10 min, when 6 mg/kg body weight of ICG was given), suggested that colchicine mainly affected the hepatocellular transport of ICG rather than the uptake of the dye by hepatocytes. Colchicine also significantly reduced the excretion of ICG (6 mg and 20 mg/kg) into bile but did not alter that of BSP (100 mg and 200 mg/kg). On the other hand, the same amount of lumicolchicine (3 mg/kg) did not have any effect on the biliary excretion of ICG. These results suggested that ICG is transported through hepatocytes into bile with the aid of the cytoplasmic microtubular system, whereas BSP is handled by hepatocytes in a different way.

Animals↗

PubMed2002

Colchicine for the prevention of postpericardiotomy syndrome.

BACKGROUND: Postpericardiotomy syndrome (PPS) is a troublesome complication of cardiac surgery, occurring in 10-45% of cases. Accepted modalities of treatment include nonsteroidal anti-inflammatory drugs, corticosteroids, and pericardiectomy in severe cases. The optimal method for prevention of PPS has not been established. Recent trial data have shown that colchicine is efficient in the secondary prevention of recurrent episodes of pericarditis. The aim of the present study was to evaluate the possible benefit of colchicine for the primary prevention of PPS in patients after cardiac surgery. To the best of our knowledge, this is the first study addressing this issue. PATIENTS AND METHODS: A prospective, randomized, double-blind design was used. The initial study group included 163 patients who underwent cardiac surgery in two centers in Israel between October 1997 and September 1998. On the 3rd postoperative day, the patients were randomly assigned to receive colchicine (1.5 mg/day) or placebo for 1 month. All were evaluated monthly for the first 3 postoperative months for development of PPS. RESULTS: 52 of the 163 patients were excluded because of postoperative complications, noncompliance, or gastrointestinal side effects of treatment. Of the 111 patients who completed the study, 47 (42.3%) received colchicine and 64 (57.7%) placebo. There was no statistically significant difference between the groups in clinical or surgical characteristics. PPS was diagnosed in 19 patients (17.1%), 5/47 cases (10.6%) in the colchicine group and 14/64 (21.9%) in the placebo group. The difference showed a trend toward statistical significance (p < 0.135). CONCLUSIONS: Colchicine may be efficacious for the prevention of PPS in patients after cardiac surgery. Further evaluations in larger clinical trials are warranted.

Adult↗

PubMed2002

Colchicine myoneuropathy in a renal transplant patient.

Colchicine is widely employed for the treatment of gout in renal transplant patients where NSAIDs are contra-indicated and allopurinol prophylaxis is often avoided due to concomitant azathioprine immunosuppression. We report here a case of colchicine-induced myoneuropathy in a renal transplant recipient. Our patient had myalgia, muscle weakness, elevated creatine kinase levels, myopathic changes on electromyography and peripheral neuropathy. Withdrawal of colchicine resulted in recovery within 4 weeks. Renal transplant recipients are likely to be at greater risk of colchicine-induced myoneuropathy due to the unique concurrence of risk factors predisposing to toxicity in such patients. These risk factors include the high incidence of gout in this population, widespread use of colchicine as first-line therapy, impaired renal function and concomitant cyclosporin treatment. The diagnosis should be considered in any renal transplant recipient receiving the drug who develops myopathy. Prompt withdrawal of colchicine therapy should result in rapid clinical and biochemical improvement.

Aged↗

PubMed1997

Chronic colchicine treatment does not impair glucose tolerance in familial Mediterranean fever patients.

OBJECTIVE: To investigate a long-term colchicine treatment in inhibiting normal release of insulin, in response to a glucose load. SETTING: The Heller Institute of Medical Research, Sheba Medical Center, Tel-Hashomer. PATIENTS: Thirty-one familial Mediterranean fever (FMF) patients, treated continuously with colchicine (1.0-2.0 mg.day-1) for 2-13 years. METHODS: A standard oral glucose tolerance test (OGTT) was performed to study the effect of long-term colchicine treatment on glucose-induced insulin response. An intravenous glucose tolerance test (IVGTT) was then performed on randomly chosen FMF patients (n = 9) and age-matched controls (n = 5). Glucose was administered 30 min after intravenous colchicine (2 mg) infusion. The sum of 1st- and 3rd-min insulin levels served as an index of early-phase insulin release. RESULTS: Based on the Office Guide to Diagnosis of Glucose Intolerance [13], one subject exhibited impaired glucose tolerance and two others had abnormal dynamics of glucose during the test but normal values at 120 min. Insulin values were normal in all participants. No significant differences were found in maximal glucose and insulin concentration, nor in the insulin release index between FMF colchicine-treated and healthy controls. CONCLUSIONS: Based on these findings, no impairment in glucose dynamics could be demonstrated in chronically colchicine treated patients, compared to untreated controls.

Administration, Oral↗

PubMed1998

Colchicine-induced cell death and proliferation in the olfactory epithelium and vomeronasal organ of the mouse.

The cytotoxic agent colchicine induced apoptotic cell death and subsequent regeneration in the mouse olfactory epithelium and vomeronasal organ. The TUNEL method revealed the presence of many apoptotic bodies in the middle to basal region of the septal olfactory epithelium and vomeronasal organ near the boundary of the respiratory epithelium at 1 day after a single i.p. injection of colchicine (4 mg/kg b.w.). In some regions of the third and the fourth nasal turbinates, massive apoptosis was observed in the olfactory epithelium. Electron micrographs of the septum showed that immature olfactory cells and globose basal cells were killed by the colchicine and had been phagocytized by the supporting cells and macrophages. In the vomeronasal organ, immature sensory cells and precursors died in response to the colchicine. In response to cell death, active proliferation of precursor cells (globose basal cells) and subsequent regeneration of olfactory cells occurred in the olfactory epithelium and vomeronasal organ. Incorporation of the mitotic tracer BrdU by precursor cells reached its peak at 4 days after colchicine treatment in the vomeronasal organ, and at 6 to 7 days in the olfactory epithelium; however, in some regions in the third and the fourth nasal turbinates, where many olfactory cells and globose basal cells had died by colchicine effect, the regeneration did not occur even in 1 month, forming the epithelium of only supporting cells and horizontal basal cells. In the next month, these regions became normal olfactory epithelium. This suggests that the globose basal cells in the surrounding normal olfactory epithelium might invade these regions to give rise to the olfactory cells.

Animals↗

PubMed2005

Colchicine treatment differently affects releasable thyrotropin-releasing hormone (TRH) pools in the hypothalamic paraventricular nucleus (PVN) and the median eminence (ME).

1. Hypophysiotropic thyrotropin-releasing hormone (TRH) is synthesized in the hypothalamic paraventricular nucleus (PVN) and transported to the median eminence (ME) where it enters the hypophyseal portal blood. TRH in the ME is situated exclusively in nerve terminals, whereas TRH in the PVN and septum is of extrinsic (nerve terminals) as well as intrinsic (perikarya) origin. 2. To determine the source and possible differential regulation of TRH release from these structures, we blocked TRH axonal delivery by i.c.v. administration of colchicine into the lateral cerebral ventricle of euthyroid or hypothyroid rats in doses of 7.5 mug or 7.5, 75 and 100 microg, respectively, two days prior to the evaluation of the TRH secretion from the PVN, ME and the septum in vitro. 3. In euthyroid rats a low dose of colchicine did not significantly affect plasma TSH. The secretory response to both ethanol in an isosmolar medium and a high K+ in the ME as well as the PVN explants was well preserved. However, colchicine treatment resulted in the significant increase of basal secretion of TRH from the PVN. 4. Hypothyroidism induced by 200 mg/l methimazole in drinking water for two weeks resulted in growth arrest, elevated plasma thyrotropin and decreased TRH content in the PVN and the ME. Colchicine partially decreased elevated plasma thyrotropin and increased the TRH content in the PVN and its basal release in vitro which was independent of extracellular Ca2+. Interestingly, a TRH release from the PVN could not be further stimulated either by K+ membrane depolarization or by ethanol. TRH responsiveness to the stimulation remained unaffected in the ME. The effect of colchicine on the septal TRH secretion was intermediate between the effect observed in the PVN and the ME. 5. In conclusion, the absence of a TRH secretory response to stimuli in the PVN after colchicine disruption of the microtubules and Golgi system suggests that stimulated TRH release observed from the PVN explants in vitro occurs from nerve terminals projecting to the PVN from other brain regions. The independence from extracellular calcium implies that TRH released under the non-stimulating conditions occurs most likely via the constitutive secretory pathway from dendrites and/or perikarya. Regulation of septal TRH is markedly different from the hypophysiotropic one.

Animals↗

PubMed1987

Survival of patients with primary (AL) amyloidosis. Colchicine-treated cases from 1976 to 1983 compared with cases seen in previous years (1961 to 1973).

Primary amyloidosis has a variable course, but is generally associated with a short life expectancy. To date, no specific therapy has been available. Fifty-three patients with AL amyloidosis seen between 1976 and 1983 were treated with colchicine, and their clinical course and survival were compared with that in 29 other patients seen between 1961 and 1973. Of the variables measured, the treatment, the patient's sex, and the time interval from diagnosis to referral of treatment were significantly associated with length of survival. Median survival for the colchicine-treated patients was 17 months, compared with six months for the non-colchicine-treated patients. A surprising finding was the longer life span in female patients (median eight months versus four and a half months in the non-colchicine-treated group, and 25.5 months versus 10 month in the colchicine-treated group). The study suggests that colchicine has improved the life expectancy in AL amyloidosis. Although it is not a specific therapy, it may be a reasonable form of adjunctive treatment in this complex disorder.

Amyloidosis↗

PubMed1988

The effects of colchicine on prostaglandin I2 and thromboxane A2 biosynthesis in the rat dental pulp.

Pulp tissues isolated from rats treated with either colchicine (0.5, 0.75 or 1.0 mg/kg) or beta-lumicolchicine (1.0 mg/kg) for 24 h were incubated in Tyrode buffer. Prostaglandin (PG) I2 and thromboxane (TX) A2 released into the medium were determined by radioimmunoassay as their stable metabolites, 6-keto-PGF1 alpha and TXB2, respectively. Colchicine generally enhanced PGI2 and TXA2 production concomitantly with hypocalcaemia, except that 0.5 mg/kg dosage had no significant effects. This enhancement was greater in PGI2 than in TXA2 synthesis, but was not observed in PGI2 release from aortic tissue. beta-Lumicolchicine (1.0 mg/kg) had no effect on PG and TX synthesis, nor on serum calcium. Kinetic studies revealed that after a lag period of more than 12 h, 1.0 mg/kg colchicine caused a progressive increase in the production of PGI2 and TXA2, which reached a maximum at 24 h and decreased thereafter gradually to the basal level within 168 h (7 days). In contrast, the hypocalcaemic effect of colchicine appeared rapidly, reached a maximum within 3 h and gradually recovered to the control level within 7 days. Colchicine at concentrations of 1-1000 microM had no stimulatory effect on PGI2 and TXA2 biosynthesis when incubated in vitro with isolated pulp tissues; it was inhibitory at higher concentrations. The enhancing effect of colchicine treatment on PGI2 and TXA2 production in dental pulp tissue may be caused indirectly by interaction of this agent with microtubules, but the precise mechanisms are unclear. Thus, a drug known to affect dentinogenesis modifies arachidonic-acid metabolism in dental pulp.

Animals↗

PubMed1983

In vivo effects of colchicine on milk fat globule membrane.

Milk secretion in lactating goats was suppressed reversibly by infusing colchicine (2.5 to 5 mg) into one half of the udder via the teat canal. Fat globules were isolated from milks before, during and after (96 h post-infusion) this suppression. Protein, phospholipid, cholesterol (free and esterified), 5'-nucleotidase activity and peptide patterns by gel electrophoresis of these globule samples were determined. Association of [14C]colchicine with milk fat globules in vivo and in vitro also was investigated. Amounts of protein, phospholipid and free cholesterol per g of globule and 5'-nucleotidase per mg of globule protein fall following colchicine infusion. The nature of these changes suggests that the supply of membrane for milk secretion is restricted as a result of the drug treatment. Patterns of globule peptides by gel electrophoresis were qualitatively similar during the experimental period. However, a major globule glycoprotein, Mr = 52 000, showed a significant (3-fold) increase relative to the other principal peptide bands during the period of reduced milk flow. Analysis of milks for radioactivity following infusion of [14C]colchicine revealed that a portion of activity returning in milk is associated with fat globules. This activity peaked at 72 h post-infusion. Evaluation of [14C]colchicine binding to milk fat globules in vitro yielded evidence that the drug binds to the cytoplasmic, but not the exterior surface of the globule membrane. Colchicine's inhibition of milk synthesis and secretion is discussed.

Animals↗

PubMed1978

Reversible hyperphagia and obesity following intracerebral microinjections of colchicine into the ventromedial hypothalamus of the rat.

Colchicine, a drug which produces a reversible inhibition of intraaxonal transport and synaptic transmission, was used as a reversible neural blocker to investigate the role of the ventromedial hypothalamus (VMH) in the control of ingestive behavior and body weight regulation. Male Sprague-Dawley rats received intracranial microinjections of colchicine into the VMH. Volume and concentration of the colchicine solution were varied to assess specificity of action and dose-response relationship. When colchicine (2 and 4 microgram) was microinjected bilaterally into the VMH, there was a dose-dependent increase in food and water intakes and body weight gain which lasted several days. The acute period of hyperphagia was followed by a marked depression in feeding which persisted until body weight was lowered to control levels. This suppression of feeding appeared to be a consequence of the preceding period of hyperphagia and obesity, since colchicine-treated rats which were pair-fed with controls to prevent obesity continued to maintain normal food intake and body weight gain when later fed ad libitum. The results of this study confirm the importance of the VMH in the long term regulation of feeding, and indicate that reversible neuronal blocking with colchicine is a useful technique for investigating the neural substrates of feeding and other behaviors.

Animals↗

PubMed1987

The effects of a reversible colchicine-induced lesion of the anterior ventral region of the third cerebral ventricle in rats.

Colchicine was injected into the region of the organum vasculosum lamina terminalis/anterior region of the third cerebral ventricle (OVLT/AV3V) to produce a temporary disruption of the nervous connections of this area and the rest of the anterior hypothalamus, but to maintain the vascular connections intact. Rats were kept in metabolism cages throughout the experiment and food and water intake plus urine and electrolyte excretion and body weight were measured each day. Food intake, body weight gain and urine and sodium excretion were reduced for several days after the injection of colchicine and the rats went into a marked positive sodium balance from the third day postinjection. Following 24 h water deprivation, 7 days after the colchicine injection, water intake was increased for 2 days. Urine and electrolyte excretion and food intake were also increased on the second day after the deprivation. Following a second deprivation, 10 days later, the colchicine-injected animals behaved as the control rats had done during both the deprivation periods. Injections of colchicine into the OVLT region of the AV3V, that would have blocked neural activity while maintaining a constant blood supply, produced some of the characteristics of a 'normal' lesion in this area; the rats decreased sodium excretion and increased their water intake in response to water deprivation. Therefore, colchicine may provide a useful means of investigating what role the constituent areas of the AV3V play in body fluid regulation.

Animals↗