ABSTRACT
There are controversial reports on the effect of diabetes on the pain threshold. We used male Wistar rats to see the effect of streptozotocin induced diabetes on the tail flick, vocalisation and vocalisation after discharge responses. These represent the spinal, lower brain stem and hypothalamic responses respectively. The effect of morphine in these parameters was studied for both the control and diabetic group. In diabetic rats, the pain threshold was increased. However, this increase was not significant. Morphine produced significant analgesia after thirty minutes for tail flick and vocalisation responses and after fifteen minutes for after discharge in the control group. The antinociceptive effect of morphine was delayed and reduced for all three pain threshold confirming the antagonistic action of glucose on opiate receptors.
Subject(s)
Analgesics, Opioid/pharmacology , Animals , Diabetes Mellitus, Experimental/chemically induced , Male , Morphine/pharmacology , Naloxone/pharmacology , Narcotic Antagonists/pharmacology , Pain , Pain Measurement , Rats , Rats, Wistar , Receptors, Opioid, delta/antagonists & inhibitors , StreptozocinABSTRACT
Stress is known to produce analgesia. The pain threshold is altered in diabetes. We studied the effect of 1 hr of immobilisation stress on pain threshold in male Wistar rats. The same effect was tested in streptozotocin induced diabetic rats. The pain threshold of tail flick, vocalisation and vocalisation after discharge increased in the control group after the stress procedure. Significant analgesia was also obtained in diabetic rats, for flick and after discharge pain threshold. However the vocalisation threshold was not altered, probably due to the antagonistic action of glucose on opiate receptor at the level of brain stem.
Subject(s)
Analgesia , Animals , Blood Glucose/metabolism , Brain Stem/metabolism , Diabetes Mellitus, Experimental/chemically induced , Immobilization , Male , Pain Threshold , Rats , Rats, Wistar , Receptors, Opioid/antagonists & inhibitors , Streptozocin , Stress, Physiological/complications , Vocalization, AnimalABSTRACT
The present study was designed to investigate the role of central adrenoceptors in the hypotensive effect of intracerebroventricular (ICV) injection of norepinephrine (NE) in conscious rabbits. Experiments were carried out on 19 adult rabbits (oryctolagus cuniculus) of either sex. A dose-dependent hypotensive response to ICV injection of NE was observed with no significant change in heart rate. The hypotensive response of NE was blocked 74.2 +/- 0.7% by yohimbine (alpha-2 adrenergic blocker), and 25.0 +/- 0.5% by metoprolol (beta-1 adrenergic blocker). NE response was not affected either by prazosin or butoxamine (alpha-1 and beta-2 adrenergic blockers respectively). The results suggest that the dose-dependent hypotensive response of ICV administered NE is mediated through alpha-2 and beta-1 central adrenoceptors.
Subject(s)
Adrenergic alpha-Agonists/administration & dosage , Adrenergic alpha-Antagonists/administration & dosage , Adrenergic beta-Antagonists/administration & dosage , Animals , Blood Pressure/drug effects , Butoxamine/administration & dosage , Dose-Response Relationship, Drug , Female , Heart Rate/drug effects , Injections, Intravenous , Injections, Intraventricular , Male , Metoprolol/administration & dosage , Norepinephrine/administration & dosage , Prazosin/administration & dosage , Rabbits , Yohimbine/administration & dosageABSTRACT
The effect of cyproheptadine (CPH) on glucose tolerance, serum immunoreactive insulin (IRI) and structure of pancreatic islets in albino rats has been studied. Hyperglycemia with glucose intolerance was observed after 10 days of administration of CPH (40 mg/kg, ip). There was insignificant change of fasting IRI after the treatment. Histological studies indicated degranulation and vacuolation of beta cells with enlargement of capillaries. Improvement in blood glucose, glucose tolerance and structure of islets with proliferation of small pancreatic ducts and cell cords were observed 10 days after the withdrawal of CPH.
Subject(s)
Animals , Blood Glucose/analysis , Cyproheptadine/pharmacology , Cytoplasmic Granules/drug effects , Glucose Tolerance Test , Hyperglycemia/chemically induced , Insulin/blood , Islets of Langerhans/drug effects , Male , Rats , Rats, Inbred StrainsABSTRACT
Effects of intrahypothalamic and intraventricular microinjections of norepinephrine (NE) were studied in fasted albino rats. Applications of NE into ventromedial hypothalamus (VMH), medial part of lateral hypothalamus (LH) and lateral ventricle (LV) caused marked but short lasting decrease in food intake, whereas lateral part of LH was insensitive to NE administration. Decrease in water intake seemed secondary to decrease in food intake. Decrease in food intake could not be attributed to the alteration of body temperature. This study explains the mechanism of anorexigenic action of amphetamine and the mechanism of hyperphagia following destruction of the ventral noradrenergic bundle.
Subject(s)
Animals , Body Temperature/drug effects , Drinking Behavior/physiology , Feeding Behavior/physiology , Hypothalamus/drug effects , Hypothalamus, Middle , Injections, Intraventricular , Male , Microinjections , Norepinephrine/administration & dosage , Rats , Rats, Inbred StrainsABSTRACT
Experiments were carried out in albino rats to find out the effect of propranolol, priscol and atropine on post-hemorrhagic erythropoiesis. Administration of either propranolol or priscol decreased reticulocyte response following hemorrhage, whereas administration of atropine produced no change. The results indicate that alpha as well as beta adrenergic systems participate in the control of erythropoiesis following hemorrhage, whereas parasympathetic system does not take part.