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1.
Pol J Vet Sci ; 25(1): 183-186, 2022 Mar.
Article in English | MEDLINE | ID: mdl-35575991

ABSTRACT

Twenty apparently healthy buffaloes were withdrawn of feed and water for 48 hours. Buffaloes were administered with fluids and were subjected to endoscopy every 12 hours. Olympus™ [GIF V70] flexible video endoscope was passed through the ventral nasal meatus, the pharynx, oesophagus and then into the reticulo-rumen in physically restrained buffaloes. The entire reticulum and part of the rumen could be visualized, when the animals were off feed and water for at least 48 hours and evacuations of rumen contents were done even after 48 hours of starvation to visualize the rumen in six buffaloes. The reticulum appeared light brown to pink coloured with honeycomb shape and the rumen appeared smooth, shiny pink, with numerous papillae throughout its surface. The procedure was well tolerated by all the buffaloes and satisfactory reticular and ruminal images could be obtained including biopsy.


Subject(s)
Bison , Buffaloes , Animals , Endoplasmic Reticulum Stress , Endoscopy, Gastrointestinal/veterinary , Rumen/pathology , Water
2.
Trop Anim Health Prod ; 53(4): 412, 2021 Jul 26.
Article in English | MEDLINE | ID: mdl-34308515

ABSTRACT

Recently, inclusion body hepatitis (IBH) outbreaks have been increasingly reported in different regions of India, particularly in broiler flocks. The present study was undertaken to characterize fowl adenovirus associated with IBH in chicken and assessment of its pathogenicity. Liver samples were collected from fowl adenovirus (FAdV) suspected 100 commercial broiler and six broiler breeder flocks from eleven different States of India from 2016 to 2019. All the samples were subjected to 897-bp FAdV hexon gene-specific PCR for confirmation and primary chicken liver cells were used to isolate the field FAdVs. Sequencing and phylogenetic analysis of 897-bp FAdV hexon gene revealed that all the isolates have showed close evolutionary relationship with fowl adenovirus serotype 11 of species D. For pathogenicity assessment, 0.5 ml of 106.5 TCID50/ml of field FAdV serotype 11 isolate was orally inoculated in 1-day-old SPF chicks and observed for 21 days. This experimental study revealed that there was no mortality in infected chicks and showed clinical signs of dullness, depression and diarrhoea between third and fifth day of oral inoculation. The FAdV was reisolated and confirmed by PCR from experimentally infected chicken. Based on this study, among all serotypes, FAdV serotype 11 is involved in pathogenesis of inclusion body hepatitis in broiler-type chickens in India.


Subject(s)
Adenoviridae Infections , Aviadenovirus , Hepatitis , Poultry Diseases , Adenoviridae Infections/epidemiology , Adenoviridae Infections/veterinary , Animals , Aviadenovirus/genetics , Chickens , Inclusion Bodies , India/epidemiology , Molecular Typing/veterinary , Phylogeny , Poultry Diseases/epidemiology , Virulence
3.
Br Dent J ; 222(11): 849-858, 2017 Jun 09.
Article in English | MEDLINE | ID: mdl-28703151

ABSTRACT

Objective The objective of this systematic review is to evaluate the survival rate of resin bonded bridges (RBBs) and understand the relationship between various prognostic factors and survival rate.Methods An electronic medline and hand search were carried out to identify prospective studies on RBBs. Critical appraisal of the studies was done and data was extracted from selected studies. Survival rate was estimated with random effect Poissons regression using R software. Influence of location and luting cements was estimated using odds ratio and forest plots using CMA software.Results The predicted survival rate for 5 and 10 years are 83.6% and 64.9%, respectively. Functional survival after rebonding has not been considered in this study. It is expected that functional survival will be higher than event free survival. Debonding of the restoration (78%) is the most common type of failure followed by porcelain fracture (13%). Bridges cemented with Panavia showed the highest survival rate (67%) among the luting cements analysed for 5 years. Retentive tooth preparation, preparation confined to enamel, silicoating, supra gingival margins, Ni-Cr or Co-Cr alloys and no occlusion on pontic in lateral excursions have been reported to be associated with better survival rates. Anterior RBBs were found to be more retentive than posterior RBBs. Pooled odds for retention of RBB in anterior segment when compared to posterior is 1.915 (95%CI - 0.847-4.329). RBBs placed in maxilla were found to be more retentive than bridges placed in mandible. Pooled odds for retention of RBB in maxilla when compared to mandible is 1.774 (95%CI - 0.803-3.917).Conclusion and recommendations Replacement of missing teeth with resin-bonded fixed partial dentures is a conservative alternative to conventional fixed partial dentures and should be included as a treatment option wherever possible. There are numerous factors that influence the longevity of RBBs. To achieve successful long-term survival, careful case selection and consideration of various variables is crucial. There is a clear and urgent need for well controlled studies to better understand the effects of these prognostic factors.


Subject(s)
Composite Resins , Denture, Partial, Fixed, Resin-Bonded , Dental Bonding/methods , Dental Restoration Failure , Denture Design , Denture Retention , Humans , Prognosis
4.
Vet World ; 8(11): 1305-9, 2015 Nov.
Article in English | MEDLINE | ID: mdl-27047034

ABSTRACT

AIM: To report the successful recovery of few dairy cattle from botulism in response to a modified therapeutic strategy. MATERIALS AND METHODS: Seventy four naturally-occurring clinical cases of bovine botulism encountered during the period of 2012-2014 which were confirmed by mouse lethality test became material for this study. Affected animals were made into three groups based on the treatment modifications made during the course of study. RESULTS AND DISCUSSION: With the modified therapeutic regimen, 17 animals recovered after 7-10 days of treatment. Clinical recovery took 2-30 days. Animals which were not given intravenous fluid and calcium recovered uneventfully. Cattle which were already treated with intravenous fluids, calcium borogluconate, and antibiotics did not recover. They were either died or slaughtered for salvage. CONCLUSION: In cattle with botulism, administration of Vitamin AD3E and activated charcoal aid the clinical recovery. Besides, strictly avoiding anti-clostridial antibiotics, fluid therapy, and calcium therapy may facilitate the clinical recovery. Upon fluid administration, the pulmonary congestion existed in the ailing cattle might have worsened the anoxia. Administration of antibiotics like penicillin, aminoglycosides, and tetracyclines further worsen the neuronal paralysis by increasing the availability of botulinum neurotoxin. Cattle in early botulism have fair chances of recovery with the modified therapy.

5.
Ann R Coll Surg Engl ; 96(1): 104E-105E, 2014 Jan.
Article in English | MEDLINE | ID: mdl-24417856

ABSTRACT

Spontaneous choledochoduodenal fistulas (CDFs) are rare. The most common aetiology is penetrating duodenal ulcers, observed in 80% of cases. Even in areas where acid peptic disease is common, tuberculosis should be considered as a cause, especially in developing countries like India, where tuberculosis is common. The management of CDF due to acid peptic disease is predominantly surgical while healing of tuberculous CDF has been reported with antitubercular treatment. A preoperative diagnosis of tuberculous CDF by endoscopic biopsy from the duodenal ulcer or image guided fine needle aspiration if abdominal lymph nodes are present can eliminate the need for surgery and achieve a cure with antitubercular treatment. The CDF in this case was due to caseation of periduodenal lymph nodes rupturing into the duodenum and the bile duct.


Subject(s)
Biliary Fistula/microbiology , Duodenal Diseases/microbiology , Duodenal Ulcer/microbiology , Intestinal Fistula/microbiology , Tuberculosis, Gastrointestinal/diagnosis , Biliary Fistula/surgery , Duodenal Diseases/surgery , Duodenal Ulcer/surgery , Endoscopy, Digestive System/methods , Humans , Intestinal Fistula/surgery , Male , Middle Aged
6.
Int J Clin Exp Pathol ; 6(7): 1272-81, 2013.
Article in English | MEDLINE | ID: mdl-23826408

ABSTRACT

Neuro-tropism is a major feature in many viral infections. Chandipura virus produces neurological symptoms in naturally infected young children and experimentally infected suckling mice. This study was undertaken to find out the neuro-invasive behaviour of Chandipura virus in suckling mice. The suckling mice were infected with the virus via footpad injection. Different tissues were collected at 24-h intervals up to 96-h post infection and processed for virus quantification and histological study. Further confirming the virus predilection to nerves tissues, the adult mice were inoculated with the virus via different routes. The suckling mice experimental results revealed a progressive replication of virus in spinal cord and brain. The progressive-virus replication was not observed in the other tissues like kidney, spleen, liver etc. Histo-pathological lesions noticed in the spinal cord and brain tissues suggested the extensive damages in these tissues. In adult mice experiment, the virus replication observed only in the brain of the mice infected via intra-cerebral route. From this study, we conclude that nervous tissues are predilection sites for Chandipura virus replication in suckling and adult mice. In suckling mice, virus might transmit through nervous tissues for dissemination. In contrast, the adult mice the nervous terminal might not pick up the virus through footpad infection. The pathogenesis in mice might be due to the virus replication mediated damage in the central nervous system.


Subject(s)
Brain/virology , Central Nervous System Viral Diseases/virology , Neurons/virology , Rhabdoviridae Infections/virology , Spinal Cord/virology , Vesiculovirus/pathogenicity , Virus Internalization , Animals , Animals, Suckling , Brain/pathology , Central Nervous System Viral Diseases/pathology , Chlorocebus aethiops , Disease Models, Animal , Mice , Neurons/pathology , RNA, Viral/metabolism , Rhabdoviridae Infections/pathology , Spinal Cord/pathology , Time Factors , Vero Cells , Vesiculovirus/genetics , Vesiculovirus/growth & development , Viral Load , Virulence , Virus Replication
8.
Pak J Biol Sci ; 16(23): 1776-80, 2013 Dec 01.
Article in English | MEDLINE | ID: mdl-24506047

ABSTRACT

Milk samples from 206 apparently healthy buffaloes of marginal farmers maintained under the prevailing field conditions were screened for Subclinical Mastitis (SCM) to determine its prevalence and etiology by White Side Test (WST), California Mastitis Test (CMT), Somatic Cell Count (SCC) and Bacteriological examination. 26.20% of animals were positive for SCM in SCC and bacteriological examination. Prevalence in graded Murrah buffaloes were found to be higher compared to graded Surti and Non-descript breeds. The prevalence of SCM was highest in above 6th stage of lactation. Single quarter infection (51.85%) was more common compared to multiple quarter infection. Hind (83.34%) and left side (57.41%) quarters were more prone to SCM. The indirect tests such as WST and CMT were found to be closely agreement with SCC and bacteriological examination. Due to their efficacious, easy to perform and interpret, these tests can effectively be employed to detect SCM under field conditions. Somatic cell count of = 3,00,000/mL of milk was regarded as the upper limit for normal buffaloes. The SCC of = 3,00,000/mL of milk with positive bacterial growth were used to diagnose SCM in the present study. Staphylococcus sp. 25 (46.30%) was the most common pathogens isolated from SCM followed by Streptococcus sp. 11 (20.37%) and E. coli 06 (11.11%) of the 54 bacterial isolates. Monobacterial and mixed bacterial infections were observed in 47 (87.04%) and 7 (12.96%) cases respectively.


Subject(s)
Buffaloes , Mammary Glands, Animal/microbiology , Mastitis/veterinary , Milk/microbiology , Animals , Asymptomatic Diseases , Bacteriological Techniques/veterinary , Female , India/epidemiology , Mastitis/diagnosis , Mastitis/epidemiology , Mastitis/microbiology , Predictive Value of Tests , Prevalence , Risk Factors
9.
S Afr J Surg ; 50(2): 43-4, 2012 Mar 29.
Article in English | MEDLINE | ID: mdl-22622102

ABSTRACT

Intussusception is usually a disease of children aged between 6 months and 4 years, in which a part of a bowel telescopes into another part of the bowel. We report a case in a 60-year-old man who required resection and anastomosis. Although intussusception is unusual in adults, awareness of the differences in symptoms and causes should be borne in mind when adults present with intestinal obstruction.


Subject(s)
Intestine, Small/surgery , Intussusception/etiology , Intussusception/surgery , Jejunal Diseases/etiology , Jejunal Diseases/surgery , Lipomatosis/complications , Lipomatosis/surgery , Anastomosis, Surgical , Diagnosis, Differential , Humans , Intussusception/diagnosis , Jejunal Diseases/diagnosis , Lipomatosis/diagnosis , Male , Middle Aged
10.
Avian Pathol ; 36(6): 481-5, 2007 Dec.
Article in English | MEDLINE | ID: mdl-17994327

ABSTRACT

The effect of vaccination of chickens with different inactivated vaccines against experimental Ornithobacterium rhinotracheale challenge was investigated. Eight different vaccines, with different inactivating substances (Formalin and thiomersal) and with or without adjuvant (mineral oil, alum and aluminium hydroxide gel), were produced. Following vaccination of experimental chickens at week 8 with formalin-inactivated mineral oil adjuvant bacterin, the mean O. rhinotracheale antibody titres rose to 5.88 2log 21 days after primary vaccination and enhanced to a titre of 6.59 2log 21 days after booster vaccination. The bacterin in mineral oil adjuvant induced the highest serologic response and a significant decrease of lesions such as air sacculitis and pneumonia in vaccinated birds compared with the unvaccinated challenge control birds. The bacterin in either alum or aluminium hydroxide gel adjuvant induced a moderate serologic response and a decrease of lesions compared with the unvaccinated challenge controls. The study showed that vaccination of layer chicken at the eighth week followed by a booster dose at the 12th week of age can effectively protect against O. rhinotracheale infections.


Subject(s)
Bacterial Vaccines/immunology , Chickens/immunology , Flavobacteriaceae Infections/veterinary , Ornithobacterium/immunology , Poultry Diseases/immunology , Poultry Diseases/prevention & control , Animals , Female , Flavobacteriaceae Infections/immunology , Flavobacteriaceae Infections/prevention & control
11.
Indian J Pediatr ; 71(2): 171-2, 2004 Feb.
Article in English | MEDLINE | ID: mdl-15053384

ABSTRACT

Gastric teratoma accounts for less than 1% of all teratomas occurring in children, usually males. These tumors may be benign or malignant and complete excision of the tumor in either case carries a good prognosis. This rare case is an addition to the few cases of gastric teratomas in females reported in world literature and presenting as an exophytic & endophytic growth.


Subject(s)
Stomach Neoplasms/diagnosis , Teratoma/diagnosis , Female , Humans , Infant , Stomach Neoplasms/surgery , Teratoma/surgery
12.
J Laryngol Otol ; 115(1): 57-9, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11233628

ABSTRACT

Oncocytomas are rare tumours that occur predominantly in the major salivary glands, particularly the parotid of older individuals. We present the exceptionally rare occurrence of an oncocytoma in the post-nasal space and its treatment for the first time via a Le Fort I osteotomy. The potential for local spread to the surrounding skull base makes it vital to achieve good oncological clearance. We found that this was possible using the Le Fort I technique and would recommend that this approach should be considered in future, when approaching such lesions.


Subject(s)
Adenoma, Oxyphilic/surgery , Nose Neoplasms/surgery , Adenoma, Oxyphilic/complications , Adenoma, Oxyphilic/pathology , Aged , Hearing Loss, Conductive/etiology , Hearing Loss, Conductive/surgery , Humans , Magnetic Resonance Imaging , Male , Microscopy, Electron , Nose Neoplasms/complications , Nose Neoplasms/pathology , Osteotomy
13.
Australas Radiol ; 43(1): 12-5, 1999 Feb.
Article in English | MEDLINE | ID: mdl-10901863

ABSTRACT

Two cases of epidermal cyst of the breast, a rare benign condition, were detected during a 3-year period in a mammographic screening programme, from 57,954 screening examinations. It is not uncommon for epidermal cysts to be initially misdiagnosed. The mammographic, ultrasound and histological features are presented. It is recommended that these lesions be resected because they possibly have malignant potential.


Subject(s)
Epidermal Cyst/diagnostic imaging , Fibrocystic Breast Disease/diagnostic imaging , Aged , Epidermal Cyst/pathology , Female , Fibrocystic Breast Disease/pathology , Humans , Mammography , Mass Screening , Middle Aged , Ultrasonography, Mammary
14.
Injury ; 29(10): 751-6, 1998 Dec.
Article in English | MEDLINE | ID: mdl-10341898

ABSTRACT

Fourteen consecutive cases with type 4 fracture of the medial epicondyle were evaluated following open reduction and internal fixation of the displaced medial epicondyle. The mean age was 9.7 years (range 6-16) and the mean follow-up was 17.2 months (range 12-24). Operative treatment yielded excellent results with no loss of functional range of motion, residual deformity or instability. There were three cases with pre-operative symptoms of ulnar nerve injury which made a good recovery following neurolysis of the ulnar nerve. Type 4 fractures are commonly associated with intra-articular entrapment of the ulnar nerve and result from serious damage to the soft tissues on the medial side of the elbow. Assessing instability is therefore of key importance, as is the intra-operative gravity stress-valgus test in assessing instability.


Subject(s)
Elbow Injuries , Fracture Fixation, Internal/methods , Humeral Fractures/surgery , Adolescent , Child , Elbow Joint/diagnostic imaging , Female , Follow-Up Studies , Humans , Humeral Fractures/diagnostic imaging , Male , Radiography , Ulnar Nerve Compression Syndromes/etiology , Ulnar Nerve Compression Syndromes/surgery
15.
Arch Int Pharmacodyn Ther ; 329(3): 360-78, 1995.
Article in English | MEDLINE | ID: mdl-8546536

ABSTRACT

The aim of the present study was to investigate the mechanism of the biphasic blood pressure response to the 5-hydroxytryptamine2 (5-HT2) receptor agonist, alpha-methyl-5-HT (alpha-Me-5-HT) in anaesthetized rats. In conscious rats, 5-HT (2.5-15 micrograms/kg, i.v.) produced typical triphasic blood pressure responses at the higher doses. In anaesthetized rats, 5-HT produced only hypotensive responses at all doses. In conscious rats, i.v. injections of alpha-Me-5-HT (5-125 micrograms/kg) produced dose-dependent increases in mean arterial pressure with concomitant bradycardia. However, in inactin-anaesthetized rats, alpha-Me-5-HT produced biphasic blood pressure responses consisting of an initial pressor response followed by a longer lasting depressor phase. In anaesthetized rats, the 5-HT1A antagonist, spiroxatrine (1 mg/kg), and the 5-HT3 receptor antagonist, MDL72222 (0.3 mg/kg), selectively diminished the hypotensive phase without affecting the pressor phase. The 5-HT1/5-HT2 antagonist, methysergide (0.5 mg/kg), and the selective 5-HT2 antagonist, ketanserin (50 micrograms/kg), completely abolished all responses to alpha-Me-5-HT. Pretreatment with the 5-HT-selective uptake inhibitor, fluoxetine (1 mg/kg), produced a significant attenuation of the hypotensive response whilst enhancing the pressor response. Pretreatment with the 5-HT depletor, p-chlorophenylalanine (3 x 100 mg/kg/day), produced an attenuation of the hypotensive phase while the pressor response was augmented. The selective 5-HT2/5-HT2C agonist, 1-(2,5-dimethoxy-4-iodophenyl)-2- amino-propane (5-200 micrograms/kg, i.v.), produced dose-dependent pressor responses in anaesthetized rats but no hypotensive responses were observed. The results show that the 5-HT2 agonist, alpha-Me-5-HT, produces a biphasic blood pressure response in anaesthetized rats which is not seen in conscious rats. The hypotensive response is due to a nonselective activation of 5-HT1 and 5-HT3 receptors through release of 5-HT.


Subject(s)
Blood Pressure/drug effects , Serotonin Receptor Agonists/pharmacology , Serotonin/analogs & derivatives , Amphetamines/pharmacology , Anesthesia , Animals , Dose-Response Relationship, Drug , Fenclonine/pharmacology , Fluoxetine/pharmacology , Heart Rate/drug effects , Male , Rats , Rats, Sprague-Dawley , Serotonin/pharmacology , Serotonin Agents/pharmacology , Serotonin Antagonists/pharmacology , Selective Serotonin Reuptake Inhibitors/pharmacology
16.
Eur J Pharmacol ; 276(1-2): 183-90, 1995 Mar 24.
Article in English | MEDLINE | ID: mdl-7781688

ABSTRACT

The effect of chronic i.v. infusion of the 5-HT1 receptor agonist, 5-carboxamidotryptamine (5-CT), was evaluated during the development of deoxycorticosterone acetate-salt (DOCA-salt) hypertension in rats over 4 weeks. Vehicle-treated (n = 10) Sprague-Dawley rats given DOCA (100 mg/kg, s.c.) and 1% saline as drinking fluid developed hypertension with systolic blood pressure reaching 194.6 +/- 8.99 mm Hg at 27 days. In DOCA-salt rats treated with 5-CT infusions (15.0 micrograms/kg per day, n = 10) for 4 weeks via osmotic minimpumps, systolic blood pressure was significantly lower by 41.7 mm Hg at day 27 when compared to vehicle-treated DOCA-salt rats. Systolic blood pressure values on day 27 in 5-CT-treated DOCA-salt rats were however greater than those in vehicle-treated control rats which were not given DOCA. Systolic blood pressure in 5-CT-treated DOCA-salt rats was significantly lower by day 7 compared to vehicle-treated DOCA-salt rats and remained lowered for the rest of the observation period. Heart rate was significantly greater in 5-CT-treated DOCA-salt rats on day 7 when compared to vehicle-treated DOCA-salt rats. Baroreflex sensitivity on day 28 was significantly greater in 5-CT-treated DOCA-salt rats as compared to vehicle-treated DOCA-salt rats. On day 28, hypotensive responses to hexamethonium (20 mg/kg) in 5-CT-treated DOCA-salt rats were markedly reduced compared to those in vehicle-treated DOCA-salt rats.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Hypertension/prevention & control , Serotonin Receptor Agonists/pharmacology , Serotonin/analogs & derivatives , Animals , Blood Pressure/drug effects , Desoxycorticosterone , Electrolytes/blood , Heart Rate/drug effects , Male , Organ Size/drug effects , Pressoreceptors/drug effects , Pressoreceptors/physiology , Rats , Rats, Sprague-Dawley , Reflex/drug effects , Serotonin/pharmacology , Sodium Chloride
17.
J Hypertens ; 12(1): 7-14, 1994 Jan.
Article in English | MEDLINE | ID: mdl-8157947

ABSTRACT

OBJECTIVE: To investigate the hypotensive effect and mechanism of action of chronic administration of ketanserin in spontaneously hypertensive rats (SHR) and in normotensive Wistar-Kyoto (WKY) rats. METHODS AND RESULTS: SHR and WKY rats were given chronic ketanserin infusions via osmotic minipumps to minimize fluctuations in drug concentrations and receptor responsiveness. In SHR treated with intravenous infusions of 3.0 (n = 9) or 6.0 mg/kg per day (n = 8) ketanserin for 7 days, significant dose-dependent falls in systolic blood pressure (SBP) were observed during the infusion period. Heart rate did not change in either the vehicle- or the ketanserin-treated groups of SHR. In WKY rats intravenously infused with 3.0 (n = 9) or 6.0 mg/kg per day (n = 10) ketanserin, dose-dependent falls in SBP were also observed during the infusion period, with the changes reaching statistical significance at the 6.0 mg/kg per day dose. The changes in heart rate were not different from those in control rats. Pressor responses to the type 2 5-hydroxytryptamine (5HT2)-receptor agonist (+/-)-alpha-methyl-5-hydroxytryptamine (5.0-125.0 micrograms/kg), as assessed on day 7, were reduced dose-dependently in all ketanserin-infused rats. alpha 1-Adrenoceptor responses to 1.0-10.0 micrograms/kg intravenous phenylephrine were attenuated in only the WKY rats infused with 6.0 mg/kg per day ketanserin. In the SHR treated with ketanserin there was no change in the pressor responsiveness to phenylephrine. Baroreflex sensitivity on day 7 was significantly greater in the ketanserin-infused SHR than in their respective controls. Changes in baroreflex sensitivity were not significantly different in WKY rats following ketanserin infusion. CONCLUSIONS: These results show that chronic administration of ketanserin lowers blood pressure in both SHR and WKY rats. In SHR the alpha 1-adrenoceptor-blocking effects of ketanserin are compensated for, and the reduction in blood pressure by day 7 is maintained predominantly by, 5HT2-receptor blockade. In WKY rats ketanserin-induced hypotension is associated with concomitant blockade of 5HT2- and alpha 1-receptors. The present study therefore suggests a differential mechanism of action of ketanserin in hypertensive and normotensive rats during chronic treatment.


Subject(s)
Blood Pressure/drug effects , Ketanserin/pharmacology , Animals , Baroreflex/physiology , Heart Rate/drug effects , Injections, Intravenous , Male , Rats , Rats, Inbred SHR , Rats, Inbred WKY , Serotonin/analogs & derivatives , Serotonin/pharmacology , Serotonin Receptor Agonists/pharmacology , Time Factors
18.
Eur J Pharmacol ; 237(2-3): 207-13, 1993 Jun 24.
Article in English | MEDLINE | ID: mdl-8365451

ABSTRACT

The effects of chronic i.v. administration of the serotonin 5-HT1 receptor agonist, 5-carboxamidotryptamine (5-CT), on blood pressure (BP), heart rate (HR) and baroreflex sensitivity were studied in Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). Acute i.v. injection of increasing doses of 5-CT resulted in a dose-dependent reduction in mean arterial pressure (MAP) in SHR and WKY with concomitant tachycardia. In chronic experiments, 5-CT (15.0 micrograms/kg per day) or vehicle (24.0 microliters/day) was infused i.v. for 7 days, using osmotic minipumps. Systolic blood pressure (SBP) and HR were monitored daily before and during infusions. In SHR (n = 8) and WKY rats (n = 9) receiving 5-CT, a significant reduction in SBP was observed during the infusion period. HR was slightly increased in WKY rats on days 1 and 2. There were no HR changes in the SHR group. The fall in SBP was significantly larger in the SHR than in the WKY rats. Baroreflex sensitivity on day 7 was significantly greater in 5-CT-treated SHR than in control rats. There was no change in baroreflex sensitivity in WKY rats. Administration of a single dose of 5-CT (0.5 microgram/kg i.v.) on day 7 of infusion resulted in attenuated responses in WKY rats while SHR responded as their respective controls. Our data suggest that chronic administration of 5-CT results in a sustained antihypertensive effect. This is associated with an improved BRS in the SHR either as a consequence of a resetting of the baroreflex due to sustained lowering of BP or a direct action of 5-CT on baroreflex sensitivity.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Antihypertensive Agents/pharmacology , Blood Pressure/drug effects , Serotonin Receptor Agonists/pharmacology , Serotonin/analogs & derivatives , Animals , Antihypertensive Agents/administration & dosage , Dose-Response Relationship, Drug , Heart Rate/drug effects , Infusion Pumps, Implantable , Injections, Intravenous , Male , Pressoreceptors/drug effects , Rats , Rats, Inbred SHR , Rats, Wistar , Receptors, Serotonin/drug effects , Serotonin/administration & dosage , Serotonin/pharmacology , Serotonin Receptor Agonists/administration & dosage
19.
J Pharmacol Exp Ther ; 264(1): 129-34, 1993 Jan.
Article in English | MEDLINE | ID: mdl-8093720

ABSTRACT

The antihypertensive mode of action of the 5HT2 receptor antagonist, ketanserin (KET), is still a subject of controversy and has been evaluated predominantly in acute studies. Acute i.v. administration of KET (3.0 or 6.0 mg/kg) in spontaneously hypertensive rats resulted in dose-dependent reductions in mean arterial pressure accompanied by concomitant bradycardia. In these studies, the responses to single i.v. doses of the alpha-1 adrenoceptor agonist phenylephrine (10.0 micrograms/kg) and to the 5HT2 receptor agonist alpha-methyl-5-hydroxytryptamine (125.0 micrograms/kg) 30 min after injection of KET were blocked. In spontaneously hypertensive rats treated with KET infusions (3.0 mg/kg/day i.v., n = 9, or 6.0 mg/kg/day i.v., n = 8) for 7 days via osmotic minipumps, significant dose-dependent falls in systolic blood pressure were observed during the period of infusion. Heart rate did not change over the period of observation in both vehicle- and KET-treated groups. On day 7 of infusion, KET dose-dependently reduced responses to the 5HT2 agonist alpha-methyl-5-hydroxytryptamine (5.0-125.0 micrograms/kg i.v.) but did not affect responses to phenylephrine (1.0-10.0 micrograms/kg i.v.). Baroreflex sensitivity on day 7 was significantly greater in KET-infused rats as compared with control rats. These data confirm that the acute antihypertensive effects of KET are due to a combination of alpha-1 and 5HT2 receptor blockade. During chronic administration, however, the alpha-1 blocking effects of KET are compensated for, and the reduction in blood pressure by day 7 of KET chronic administration is maintained predominantly by persistent blockade of 5HT2 receptors.


Subject(s)
Hypertension/drug therapy , Ketanserin/pharmacology , Rats, Inbred SHR/physiology , Adrenergic alpha-Antagonists/pharmacology , Animals , Blood Pressure/drug effects , Blood Pressure/physiology , Heart Rate/drug effects , Hypertension/physiopathology , Infusions, Intravenous , Male , Rats , Sensitivity and Specificity , Serotonin/analogs & derivatives , Serotonin/pharmacology , Serotonin Antagonists , Serotonin Receptor Agonists/pharmacology , Time Factors
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