Deoxynivalenol (Vomitoxin)-Induced Anorexia Is Induced by the Release of Intestinal Hormones in Mice.

Deoxynivalenol (DON), also known as vomitoxin, is a mycotoxin that can cause antifeeding and vomiting in animals. However, the mechanism of DON inducing anorexia is complicated. Studies have shown that intestinal hormones play a significant part in the anorexia caused by DON. We adopted the "modeling of acute antifeeding in mice" as the basic experimental model, and used two methods of gavage and intraperitoneal injection to explore the effect of intestinal hormones on the antifeedant response induced by DON in mice. We found that 1 and 2.5 mg/kg·bw of DON can acutely induce anorexia and increase the plasma intestinal hormones CCK, PYY, GIP, and GLP-1 in mice within 3 h. Direct injection of exogenous intestinal hormones CCK, PYY, GIP, and GLP-1 can trigger anorexia behavior in mice. Furthermore, the PYY receptor antagonist JNJ-31020028, GLP-1 receptor antagonist Exendin(9-39), CCK receptor antagonist Proglumide, GIP receptor antagonist GIP(3-30)NH2 attenuated both intestinal hormone and DON-induced anorectic responses. These results indicate that intestinal hormones play a critical role in the anorexia response induced by DON.

Targeting the Cholecystokinin Receptor: A Novel Approach for Treatment and Prevention of Hepatocellular Cancer.

Hepatocellular carcinoma (HCC) is the fastest growing cancer worldwide in part due to the obesity epidemic and fatty liver disease, particularly nonalcoholic steatohepatitis (NASH). Chronic inflammation with the release of cytokines and chemokines with activation of hepatic stellate cells results in changes of the liver extracellular matrix (ECM) that predisposes to the development of HCC. Blood levels of the gastrointestinal peptide cholecystokinin (CCK) are increased in humans and mice consuming a high-fat diet. We found that the CCK-B receptor (CCK-BR) expression increased in the livers of mice with NASH. Treatment of mice with a CCK-BR antagonist, proglumide, prevented NASH, lowered hepatic inflammatory cytokines and chemokines, reduced oxidative stress, decreased F4/80+ hepatic macrophages, and prevented HCC. CCK-AR and CCK-BR expression was increased in both murine and human HCC cell lines compared with that of normal liver, and CCK stimulated the growth of wild-type and CCK-A receptor knockout HCC cells in vitro, but not CCK-BR knockout cells suggesting that the CCK-BR mediates proliferation. Proglumide therapy significantly reduced growth by 70% and 73% in mice bearing Dt81Hepa1-6 or in RIL-75 HCC tumors, respectively. IHC of a human liver tissue array with a selective CCK-BR antibody revealed staining of human HCC and no staining in normal liver. PREVENTION RELEVANCE: This investigation demonstrates the role of the gastrointestinal peptide cholecystokinin (CCK) in hepatocellular carcinoma (HCC) and how CCK-BR blockade reverses the premalignant state of the hepatic extracellular matrix hence, rendering it less susceptible to the development of HCC. Thereby, CCK-BR blockade is a novel approach for the prevention/treatment of HCC.

Dietary fat stimulates pancreatic cancer growth and promotes fibrosis of the tumor microenvironment through the cholecystokinin receptor.

The gastrointestinal peptide cholecystokinin (CCK) is released from the duodenum in response to dietary fat to aid in digestion, and plasma CCK levels are elevated with the consumption of high-fat diets. CCK is also a trophic peptide for the pancreas and has also been shown to stimulate growth of pancreatic cancer. In the current investigation, we studied the influence of a diet high in saturated fat on the growth of pancreatic cancer in syngeneic murine models before the mice became obese to exclude the confounding factors associated with obesity. The high-fat diet significantly increased growth and metastasis of pancreatic cancer compared with the control diet, and the stimulatory effect was blocked by the CCK-receptor antagonist proglumide. We then selectively knocked out the CCK receptor on the pancreatic cancer cells using clustered regularly interspaced short palindromic repeats technology and showed that without CCK-receptors, dietary fat was unable to stimulate cancer growth. We next demonstrated that dietary fat failed to influence pancreatic cancer xenograft growth in genetically engineered CCK peptide knockout mice. The tumor-associated fibrosis that is so prevalent in the pancreatic cancer microenvironment was significantly decreased with CCK-receptor antagonist therapy because fibroblasts also have CCK receptors. The CCK-receptor antagonist proglumide also altered tumor metalloprotease expression and increased tumor suppressor genes by a PCR array. Our studies confirm that a diet high in saturated fat promotes growth of pancreatic cancer and the action is mediated by the CCK-receptor pathway. NEW & NOTEWORTHY Diets high in long-chain saturated fats promote growth of pancreatic cancer independent of obesity. The mechanism through which dietary fat promotes cancer is mediated through the cholecystokinin (CCK) receptor pathway. Therapy with a CCK-receptor antagonist altered the tumor microenvironment by reducing fibrosis, increasing cluster of differentiation 8+ lymphocytes, increasing tumor suppressor genes, and thus decreasing metastases. Use of CCK-receptor antagonist therapy with standard chemotherapy for pancreatic cancer may improve response by altering the tumor microenvironment.

Isobolographic Analyses of Proglumide-Celecoxib Interaction in Rats with Painful Diabetic Neuropathy.

Preclinical Research The aim of the present study was to analyze the antihyperalgesic and antiallodynic interaction between the non-selective cholecystokinin (CCK) antagonist receptor, proglumide, and the selective cyclooxygenase-2 inhibitor, celecoxib in streptozotocin (STZ)-induced diabetic rats. Hyperalgesia was evaluated in the formalin test and tactile allodynia using von Frey filaments. Isobolographic analyses were employed to define the nature of the compound interactions, using a fixed dose ratio (0.5:0.5). Proglumide (20-160 mg/kg) and celecoxib (0.3-30 mg/kg) in these fixed dose ratio combinations induced dose-dependent antihyperalgesia and an antiallodynic effect in diabetic rats. ED40 values were calculated for the treatments and an isobologram was constructed. Theoretical ED40 values for combination proglumide-celecoxib estimated from the isobolograms for antihyperalgesic and antiallodynic activity (30.50 ± 1.90 mg/kg and 45.81 ± 4.55 mg/kg, respectively) were obtained, while experimental ED40 values for this antihyperalgesic and antiallodynic combined effect (13.83 ± 0.65 mg/kg and 17.74 ± 3.57 mg/kg; respectively) were significantly different. Coadministration of proglumide-celecoxib showed an interaction index value of 0.45 ± 0.03 for the antihyperalgesic effect and 0.39 ± 0.08 for the antiallodynic activity, indicating a synergistic interaction. These data suggest that proglumide and celecoxib can interact synergistically to reduce hyperalgesic and allodynic behaviors in diabetic neuropathy. This combination could be useful to treat neuropathic pain in diabetic patients. Drug Dev Res 78 : 116-123, 2017. ©2017 Wiley Periodicals, Inc.

Lack of Analgesic Synergy of the Cholecystokinin Receptor Antagonist Proglumide and Spinal Cord Stimulation for the Treatment of Neuropathic Pain in Rats.

OBJECTIVE: Neuropathic pain is difficult to manage and treat. Spinal cord stimulation (SCS) has become an established procedure for treating chronic neuropathic pain that is refractory to pharmacological therapy. In order to achieve better analgesia, a number of studies have evaluated the effectiveness of combining drug therapy with SCS. Cholecystokinin antagonists, such as proglumide, enhance the analgesic efficacy of endogenous opioids in animal models of pain. We previously reported that both systemic and spinal administration of proglumide enhances analgesia produced by both low- and high-frequency transcutaneous electrical nerve stimulation (TENS). Since SCS produces analgesia through endogenous opioids, we hypothesized that the analgesic effect of SCS would be enhanced through co-administration with proglumide in animals with neuropathic pain. MATERIALS AND METHODS: Male Sprague-Dawley rats (n = 40) with spared nerve injury were given proglumide (20 mg/kg, i.p.) or saline prior to treatment with SCS (sham, 4 Hz, and 60 Hz). Mechanical withdrawal thresholds of the paw were measured before and after induction of nerve injury, and after SCS. Physical activity levels were measured after SCS. RESULTS: Both proglumide and SCS when given independently significantly increased withdrawal thresholds two weeks after nerve injury. However, there was no additional effect of combining proglumide and SCS on mechanical withdrawal thresholds or activity levels in animals with nerve injury. DISCUSSION AND CONCLUSIONS: Proglumide may be a candidate for achieving analgesia for patients with refractory neuropathic pain conditions, but does not enhance analgesia produced by SCS.

Transcriptomic and behavioural characterisation of a mouse model of burn pain identify the cholecystokinin 2 receptor as an analgesic target.

Burn injury is a cause of significant mortality and morbidity worldwide and is frequently associated with severe and long-lasting pain that remains difficult to manage throughout recovery. We characterised a mouse model of burn-induced pain using pharmacological and transcriptomic approaches. Mechanical allodynia elicited by burn injury was partially reversed by meloxicam (5 mg/kg), gabapentin (100 mg/kg) and oxycodone (3 and 10 mg/kg), while thermal allodynia and gait abnormalities were only significantly improved by amitriptyline (3 mg/kg) and oxycodone (10 mg/kg). The need for relatively high opioid doses to elicit analgesia suggested a degree of opioid resistance, similar to that shown clinically in burn patients. We thus assessed the gene expression changes in dorsal root ganglion neurons and pathophysiological mechanisms underpinning burn injury-induced pain using a transcriptomic approach. Burn injury was associated with significantly increased expression of genes associated with axon guidance, neuropeptide signalling, behavioural defence response and extracellular signalling, confirming a mixed neuropathic and inflammatory aetiology. Notably, among the pain-related genes that were upregulated post-injury was the cholecystokinin 2 receptor (Cckbr), a G protein-coupled receptor known as a pain target involved in reducing opioid effectiveness. Indeed, the clinically used cholecystokinin receptor antagonist proglumide (30 mg/kg) was effective at reversing mechanical allodynia, with additional analgesia evident in combination with low-dose oxycodone (1 mg/kg), including significant reversal of thermal allodynia. These findings highlight the complex pathophysiological mechanisms underpinning burn injury-induced pain and suggest that cholecystokinin-2 receptor antagonists may be useful clinically as adjuvants to decrease opioid requirements and improve analgesic management.

Ameliorating effects of proglumide on neurobehavioral and biochemical deficits in animal model of status epilepticus.

Status epilepticus (SE) is a recurrent generalized convulsion condition and is regarded as a medical emergency with around 50% of the cases occurring in children. Besides neurobehavioral and motor deficits, SE is reportedly associated with imbalance in a number of neurochemicals in several areas of the brain. Furthermore, neuronal hyperactivity and/or excitotoxicity in such brain areas have been associated with excessive generation of free radicals. Proglumide (Pgm) is a known cholecystokinin (CCK) antagonist and any changes in the level of CCK and in the number of CCK receptors has been linked with SE. The present study was designed to investigate the possible neuroprotective effects of Pgm (0, 250, 500 and 750mg/ml/kg i.p.) on epileptic seizure activities, some neurobehavioral tests, and on some oxidative stress related parameters like lipid peroxides measured as thiobarbituric acid-reactive substance (TBARS) and total glutathione (GSH) in brain (hippocampus and striatum) of young rats that were experimentally induced with SE by lithium (Li) in 3mEq/ml/kg dose, i.p. followed 20h later by pilocarpine (Pc) in 20mg/ml/kg dose, s.c.). Besides significant anti-epileptic effect, Pgm significantly ameliorated SE-induced deterioration in cognitive behavior (in water-maze), motor performance (on rotarod), and biochemical changes in brain. It is concluded from the present study that Pgm has significant neuroprotective effects against SE and this effect may probably be due to its antioxidant activity. Pgm may prove to be a potentially effective antiepileptic drug, however, further studies are needed to ascertain this possibility.

Cholecystokinin receptor antagonist halts progression of pancreatic cancer precursor lesions and fibrosis in mice.

OBJECTIVES: Exogenous administration of cholecystokinin (CCK) induces hypertrophy and hyperplasia of the pancreas with an increase in DNA content. We hypothesized that endogenous CCK is involved in the malignant progression of pancreatic intraepithelial neoplasia (PanIN) lesions and the fibrosis associated with pancreatic cancer. METHODS: The presence of CCK receptors in early PanIN lesions was examined by immunohistochemistry in mouse and human pancreas. Pdx1-Cre/LSL-Kras transgenic mice were randomized to receive either untreated drinking water or water supplemented with a CCK receptor antagonist (proglumide, 0.1 mg/mL). Pancreas from the mice were removed and examined histologically for number and grade of PanINs after 1, 2, or 4 months of antagonist therapy. RESULTS: Both CCK-A and CCK-B receptors were identified in early stage PanINs from mouse and human pancreas. The grade of PanIN lesions was reversed, and progression to advanced lesions arrested in mice treated with proglumide compared with the controls (P = 0.004). Furthermore, pancreatic fibrosis was significantly reduced in antagonist-treated animals compared with vehicle (P < 0.001). CONCLUSIONS: These findings demonstrate that endogenous CCK is in part responsible for the development and progression of pancreatic cancer. The use of CCK receptor antagonists may have a role in cancer prophylaxis in high-risk subjects and may reduce fibrosis in the microenvironment.

[Correction of negative influence of long-term hypergastrinemia on gastric acid secretion].

We investigated the influence of long-term diminishing of gastric acid secretion in rats by H(+)-K(+)-ATPase omeprasole on the gastrin blood level and the basal gastric acid secretion. We performed an experimental analysis of possible prophylactic drugs of structural and functional changes in gastric mucosa evoked by hypergastrinemia. It was shown that following 28 days of omeprazole injections the blood gastrin level and the output of basal acid secretion increased by 189.3% and 173.9-283.7%, respectively. It was concluded that an augmentation of the output of basal acid secretion results from the development of parietal cells hyperplasia evoked by trophic action of gastrin. We also show here that agonists of nuclear peroxisome proliferator activator receptors pioglytasone and melanin effectively prevent the changes in gastric acid secretion as an index of morphological changes.

CCK1 antagonists: are they ready for clinical use?

Cholecystokinin (CCK) is a peptide hormone which is found both in the gastrointestinal tract throughout the human small intestine and nerves in the myenteric plexus of the enteric nervous system and in the central nervous system. This dual location constitutes the anatomical basis for this in functions as a hormone and a neurotransmitter implicated in the regulation of both systems. CCK regulates not only motor functions in the gastrointestinal tract like lower oesophageal sphincter relaxation, gastric secretion and emptying, gall bladder contractility and bile secretion into the duodenum, intestinal and colonic motility, but also sensory functions and plays a role in the regulation of food intake. These effects are mediated through selective receptors CCK1 and CCK2. Over the last few years, research has focused on understanding the role of CCK, its receptors with antagonists at the biological, pharmacological, clinical and therapeutic level. As far as the CCK1 antagonists is concerned, important inroads have been made in the potential role of these antagonists in the treatment of GERD, IBS and pancreatitis. They have also shown encouraging results in sphincter of Oddi dysfunction and some gastrointestinal cancers. This review focuses on the recent ad vances of the biological role of CCK and their CCK1 antagonists: their current basic and clinical status in gastroenterology, with particular emphasis on the potential therapeutic role of the CCK1 antagonists and future research directions.

Proglumide attenuates experimental colitis in rats.

Ulcerative colitis is associated with altered contractile activity and transit time of colon. On the other hand, cholecystokinin (CCK) has been shown to play an important role in regulation of gastrointestinal motor function including colonic contraction and transit. In the present study, an attempt was made to study the effect of proglumide, a CCK receptor antagonist on experimental colitis in rats. Experimental colitis was induced in male Sprague-Dawley rats by instilling 1 ml of 4% acetic acid followed by flushing with 0.5 ml air. The rats were kept in a head-down position for 30s. Finally, each rat received 1.5 ml colonic wash with 1.5 ml saline. Four groups of rats received proglumide orally (0, 250, 500 and 1000mg/kg). The first dose of proglumide was given 1 h before acetic acid challenge, whereas the second dose of proglumide was given 25 h after the first dose. Sham control rats received an equal volume of saline instead of acetic acid. Forty-eight hours after the acetic acid challenge, the colon was removed, weighed and split longitudinally and scored for injury. Part of the colon was used for histopathological study as well as analysis of myeloperoxidase (MPO) activity (as a marker of neutrophil activity). Acetic acid produced severe diarrhea and exfoliation of the colonic epithelium accompanied by extensive destruction of the mucosal interstitium. Proglumide dose dependently protected rats against acetic acid-induced increase in colon weight, diarrhea, MPO activity and colonic injury. Inhibition of CCK exerts a beneficial effect in experimental colitis. Further studies are warranted to determine the mechanism of protection and the therapeutic potential of CCK inhibitors.

[New aspects of pharmaco-therapy for acute pancreatitis].

Despite improvement in intensive medical care management, the mortality rate from severe acute pancreatitis is still high. Attempt to reduce the mortality rate, some new drugs were investigated on experimental pancreatitis and clinical cases. There have been several clinical trials of somatostatin, somatostatin analogue octreotide, and a cholecystokinin A(CCK-A) receptor antagonist, loxiglumide, for the inhibition of pancreatic secretion. On the other hand, for the inhibition of the systemic inflammatory response, many studies in the use of the platelet-activating factor(PAF) antagonist, lexipafant, were reported in clinical trials. IS-741, a new synthetic anti-inflammatory agent, has been studied on various models of experimental pancreatitis. In this paper, it is introduced the results of these new drugs on experimental pancreatitis or clinical trials.

CCK-1 receptor blockade for treatment of biliary colic: a pilot study.

BACKGROUND: Loxiglumide is a potent and selective cholecystokinin-1 (CCK-1) receptor antagonist able to inhibit gall-bladder contraction. AIM: To assess the effect of CCK-1 receptor blockade on the pain of patients with biliary colic. PATIENTS AND METHODS: Fourteen patients with biliary colic but no suspicion for acute cholecystitis, were randomly and blindly assigned to loxiglumide (50 mg i.v.) or hyoscine-N-butyl bromide (20 mg i.v.) treatment. Pain intensity was monitored by a Visual Analogue Scale. Patients with less than 80% response at 30 min, were retreated with a second injection of the same compound. RESULTS: Reduction in pain score (mean +/- S.E.M.) was faster and significantly greater in patients treated with loxiglumide (n = 7) than in controls (n = 7): 88 +/- 7% vs. 47 +/- 12% after 20 min, P < 0.05; 92 +/- 6% vs. 49 +/- 13%, after 30 min, P < 0.05. Only one of seven patients treated with loxiglumide needed a second injection at 30 min (vs. six of seven controls, P < 0.05). No adverse effect was observed after either treatment. CONCLUSIONS: Loxiglumide is highly effective in obtaining pain relief in patients with biliary colic. The analgesic effect of CCK-1 receptor blockade is superior to that of a conventional anticholinergic treatment.

The effect of cholecystokinin antagonism on postprandial lower oesophageal sphincter function in asymptomatic volunteers and patients with reflux disease.

BACKGROUND: Postprandial acid reflux is thought to be mediated by the increase in transient lower oesophageal sphincter relaxations (TLOSR) frequency and fall in lower oesophageal sphincter (LOS) pressure seen after ingestion of a meal. Studies in animals and healthy volunteers suggest that cholecystokinin (CCK) may play a role. AIM: To study the role of CCK in postprandial LOS function using the CCK antagonist loxiglumide. SUBJECTS: 10 asymptomatic volunteers (7 male, 20-29 years) and 9 patients with symptomatic gastro-oesophageal reflux (4 male, 33-66 years). METHODS: Oesophageal, LOS and gastric pressure and oesophageal pH readings were recorded for 1 h before and 2 h after intragastric infusion of a 200 kCal, 300 mL long chain triglyceride meal. Each subject underwent two studies and received intravenous loxiglumide or placebo infusion in randomized order. RESULTS: During placebo infusion, postprandial LOS pressure fell [volunteers: 17 (9-31) to 7 (1-19) mmHg (P < 0.01), patients: 15 (6-26) to 9 (2-21) mmHg (P=0.02)] and TLOSR frequency increased [volunteers: 0 (0-1) to 2 (0-7) per hour (P=0.01), patients: 0 (0-3) to 2 (0-10) per hour (P=0.03)]. Loxiglumide infusion attenuated the postprandial fall in LOS pressure and the postprandial increase in TLOSR frequency [volunteers: 0 (0-3) per hour (P=0.04 vs. placebo), patients: 0 (0-2) per hour (P=0.03 vs. placebo)], but it had only modest effects on postprandial acid exposure [volunteers: placebo 45 (0-1725) vs. loxiglumide 0 (0-443) seconds (N.S.), patients: placebo 60 (0-3442) seconds vs. loxiglumide 31 (0-1472) seconds (N.S.)]. CONCLUSIONS: Loxiglumide inhibits TLOSR and attenuates the fall in LOS pressure following a meal, but has only modest effects on postprandial gastro-oesophageal acid reflux.

Effects of short term treatment with pentagastrin, proglumide, tamoxifen given separately or together with 5-fluorouracil on the growth in the murine transplantable Colon 38 cancer.

It is well known that 5-fluorouracil (5-FU) is the most effective drug in the treatment of colon cancer, however the positive response is small, only about 20%. On the other hand, it has been postulated that the growth of colon cancer depends on many growth factors, such as gastrin and estrogens. The search for new substances increasing the antitumor effect of 5-FU has lasted for many years. The aim of the present study was to examine the effects of pentagastrin (PEN, syntetic gastrin analogue), proglumide (PRO, a blocker of gastrin receptor) and tamoxifen (TAM, a partial estrogen antagonist) given separately or together with 5-FU on proliferation, apoptosis, necrosis and proliferation/apoptosis (P/A) ratio in the murine transplantable Colon 38 cancer. The male mice were implanted with a suspension of Colon 38 cells. After 7 days, the animals were treated with PEN (250 microg/kg b.w., twice daily), PRO (100 mg/kg. b.w., twice daily), TAM (10 microg/animal) separately or together with 5-FU (60 mg/kg b.w., once) for 2 days. The incorporation of bromodeoxyuridine (BrdU) into cell nuclei was used as an index of cell proliferation (labeling index--LI). The in situ labeling of nuclear DNA fragmentation according to TUNEL method was considered as an apoptotic index (AI). It was found that 5-FU increased the apoptosis, unexpectedly increased the LI and decreased the P/A ratio when compared to control. Both PEN and PRO increased the apoptosis and in the case of PRO decreased P/A ratio when compared to control. TAM did not affect any of the examined parameters. All of the investigated substances modify the 5-FU action: PEN and PRO on AI and LI and TAM on AI and P/A ratio. Necrosis was observed in 3 tumors treated with PEN + 5-FU, in 2 tumors of PRO + 5-FU group and in 1 tumor of group with 5-FU and with PEN. Further studies are needed to elucidate if those modification of 5-FU action by the examined substances will be useful in the inhibition of the growth of Colon 38 cancer.

Therapeutic effects of loxiglumide on experimental acute pancreatitis using various models.

We investigated the therapeutic effects of a cholecystokinin A (CCK-A) receptor antagonist, loxiglumide, on various models of experimental pancreatitis. This study shows that loxiglumide ameliorated caerulein-induced acute pancreatitis in mice as previously reported. The effects of loxiglumide on hemorrhagic and necrotizing acute pancreatitis is controversial. This study, however, shows that loxiglumide improves the survival rates in necrotizing acute pancreatitis induced by intraductal injection of taurocholate, followed by caerulein injection. In addition, the administration of loxiglumide improved both the biochemical and pathological changes of edematous acute pancreatitis induced by a closed duodenal loop in rats. It is concluded that the CCK-A receptor antagonist, loxiglumide, has therapeutic and/or prophylactic effects on acute pancreatitis in various models of experimental acute pancreatitis.

Clinical evaluation of cholecystokinin-A- receptor antagonist (loxiglumide) for the treatment of acute pancreatitis. A preliminary clinical trial. Study Group of Loxiglumide in Japan.

The therapeutic effects of loxiglumide on human acute pancreatitis was investigated in 104 Japanese institutes from October 1992 to March 1994. Acute pancreatitis was diagnosed by the Japanese Criteria of Acute Pancreatitis. Soon after the diagnosis was made, one of three doses of loxiglumide (100, 300 and 500 mg/day) were injected intravenously twice a day for 14 days. The efficacy of the treatment was evaluated by clinical signs, physical signs, and biochemical findings. 189 patients were included in this trial. The clinical signs, such as abdominal pain, disappeared in 20% of the patients on the 1st day after treatment, and the rate of improvements increased thereafter. Physical signs also improved. Serum amylase levels returned to normal within 3 days after treatment, and serum lipase showed almost the same changes as serum amylase levels, but serum lipase levels in the high-dose group (500 mg/day) returned to normal more quickly compared with the other two doses. It is concluded that the cholecystokinin A receptor antagonist, loxiglumide, may become a useful drug in the treatment of acute pancreatitis in man, although more detailed investigations are needed.

The cholecystokinin antagonist proglumide enhances the analgesic efficacy of morphine in humans with chronic benign pain.

UNLABELLED: The analgesic efficacy of morphine is sometimes only partial in patients with chronic benign pain. Among the possible factors contributing to this limitation are increased levels of cholecystokinin (CCK). We performed this prospective, placebo-controlled, double-blind, cross-over study to examine the effect of proglumide, a nonspecific CCK agonist, on analgesia in patients taking morphine on a chronic basis. Forty patients with intractable pain who were taking sustained-release morphine were recruited, and we obtained results from 36 of these patients. Median visual analog scale scores before the study were 8 and 7 after the addition of placebo for 2 wk (P = 0.16), and 6 after proglumide for 2 wk (P = 0.002). Mobility was unchanged by proglumide or placebo. Of the 36 patients, 13 elected to continue receiving proglumide after the study. We conclude that proglumide enhances the analgesia produced by morphine in some, but not all, patients with chronic benign pain. IMPLICATIONS: The pain-killing effect of morphine is incomplete in some patients. Increasing doses may be needed to maintain the initial effect. The peptide cholecystokinin may be partially responsible for this. In this study, we demonstrated that the cholecystokinin antagonist proglumide increases the analgesic effect of morphine in some patients with chronic benign pain.

Proglumide as a morphine adjunct in cancer pain management.

Proglumide, a cholecystokinin (CCK) antagonist, has been shown to have agonist effects at extremely low doses on both endogenous and exogenous opioid systems. To determine the effectiveness and the side effects of proglumide as an opioid agonist, a double-blind crossover study was conducted in 60 patients with cancer pain who were treated with opioid analgesics. Forty-three patients completed both treatment arms: (a) full analgesic dose plus placebo (the patient's usual analgesic dose, individualized to drug dose and route) and (b) one-half analgesic dose plus 50 mg of proglumide. An analysis of eight pain descriptors was performed to determine whether or not these treatments were associated with a difference in patients' pain perception. The level of patient anxiety differed between the two arms, but was inconsistent over time. There were no side effects detected with proglumide, as determined by clinical monitoring and patient questionnaire. No differences in pain perception were detected between the study arms. The latter finding is consistent with an augmentation of morphine analgesia, but without additional controls, the equivalency of the two arms cannot be determined with certainty. Nonetheless, this study suggests that proglumide may have use as an opioid adjunct in patients with cancer pain.