Age-dependent Effects of Dopamine on Working Memory and Synaptic Plasticity in Hippocampal CA3-CA1 Synapses in Mice

Normal aging in mammals is accompanied by a decline in learning and memory. Dopamine plays a vital role in regulating cognitive functions, but it declines with age: During non-pathological aging, dopamine levels, receptors, and transporters decrease. Regarding the role of the dopaminergic system's changes in old age, we examined the effect of age and applied dopamine on working memory, synaptic transmission, and long-term potentiation (LTP) induction and maintenance in young adult and mature adult mice. We employed the Y-maze spontaneous alteration test to evaluate working memory. Maturation had no observed effect on working memory performance. Interestingly, working memory performance increased following intracerebroventricular administration of dopamine only in mature adult mice. We employed evoked field potential recording (in vitro) to assess the effects of age and maturation on the long-term potentiation (LTP) induction and maintenance. There was no difference in LTP induction and maintenance between young and mature adult mice before dopamine application. However, the application of dopamine on mature adult murine slices increased LTP magnitude compared to slices from young adults. According to the obtained results, it may be concluded that hippocampal neural excitability increased in mature adult subjects, and application of dopamine abolished the difference in neural excitability among young mature and adult mature groups; which was accompanied with increment of working memory and synaptic potentiation in mature adult animals.

Occurrence of ticks and tick-borne mixed parasitic microbiota in cross-bred cattle in District Lahore, Pakistan

The present study was focused on the incidence of ticks and tick-borne diseases (TTBD) in cross-bred cattle (Friesian x Sahiwal) of two farms (n = 2548) in district Lahore, Pakistan. We collected total of 572 ticks (adults and nymphs) and blood samples (10 ml) for microscopic i.e., blood smear test - Giemsa Stain (BST) and molecular analysis; Reverse Line Blot-General Primer-PCR (RLB-PCR) and Specie Specific Primer PCR (SP-PCR) from infested cattle (n = 100) from months of April to September. Results: The tick specie identified was Rhipicephalus microplus at both farms, with significant difference in infestations rate amongst both farms (p< 0.0001). The cross-bred cattle having higher ratio of Friesian blood and lower ratio of Sahiwal blood were mostly infested by ticks (p < 0.0458) and haemoparasites (p <0.474) and vice versa. The SP-PCR showed higher number of haemoparasites infection than BST, which revealed 16% T. annulata (p < 0.0001 and k value 0.485, 0.0001), 51% B. bigemina (p < 0.0001 and k value 0.485, 0.0001) and 15% A. marginale (p < 0.001 and k value 0.207, 0.001), respectively. The single infection with B. bigemina was 34% (n = 34/100) and A. marginale 6% (n = 6/100). The double infection with T. annulata/B. bigemina was 8% (n = 8/100) and B. bigemina/A. marginale 1% (n = 1/100). Whereas the triple infection with T. annulata/B. bigemina/A .marginale was 8% (n = 8/100). The phylogenetic study of isolated sequence of T. annulata revealed close homology to isolates from Iran (87%), B. bigemina to isolates from Cuba (94 to 100%) and A. marginale with isolates from Pakistan (99 to 98%).

Effects of Pasturella Multocida B:2 and its immunogens (LPS and OMP) on reproductive hormones in Nili-Ravi Buffaloes

Abstract Livestock is a fundamental part of the agriculture industry in Pakistan and contributes more than 11.53% to GDP. Among livestock species, the buffaloes are regarded as the black gold of Pakistan. Being the highest milk producers globally, Nili-Ravi buffaloes are the most famous ones. Buffaloes are affected by many endemic diseases, and "Hemorrhagic septicemia" (HS) is one of them. This study was designed to ascertain the effects of experimental exposure ofP. multocida B:2 (oral) and its immunogens, i.e., LPS (oral and intravenous) and OMP (oral and subcutaneous) on reproductive hormonal profiles in Nili-Ravi buffaloes. Repeated serum samples were collected from the jugular vein of experimental animals for 21 days (0, 02, 04, 08, 12, 16, 20, 24, 36, 48, 72, 120, 168, 216, 264, 360, 456 and 504 hours). Hormonal assays to determine the serum concentrations of Gonadotropin-releasing hormone (GnRH), Follicle-stimulating hormone (FSH), Luteinizing hormone (LH), Estrogen (E2) and progesterone (P4) were performed using (MyBioSource) commercial Elisa kits. The hormonal profile of all treatment groups of the buffalo heifers exhibited significant (P<0.05) variations as compared to the control group (G-1). These results indicate suppression in Nili-Ravi buffaloes' reproductive hormonal profile on exposure to P. multocida B:2 and its immunogens. This influence warrants that exposure to H.S may be a possible reason for delayed puberty and poor reproduction performance in Nili-Ravi buffaloes.

Comparing the Seizure-Induced Impairment of Short-Term Plasticity in Dorsal and Ventral Hippocampus in Kindled Mice

There are many differences among dorsal and ventral hippocampal neural circuits that affect the synaptic plasticity. In this study we compared the occurrence of short-term plasticity in the field excitatory post synaptic potentials (fEPSP) in dorsal and ventral hippocampal CA1 area following kindled seizures. Animals (male C57 B6/J mice, 12 weeks of age) were kindled by intraperitoneal injections of pentylenetetrazole (PTZ) and fEPSPs were recorded from dorsal and ventral hippocampal slices. Short-term plasticity was evaluated by measuring fEPSP-slope and fEPSP-area following paired-pulse stimulation delivered at three inter-pulse intervals (20, 80 and 160 ms). Obtained results showed that in control slices fEPSP-slope was greater in ventral- compared to dorsal hippocampus, but there was no difference in fEPSP-area among two regions. In hippocampal slices of kindled animals, fEPSP-slope was similar in dorsal and ventral regions, but fEPSP-area was greater in ventral- compared to dorsal hippocampus. In addition, fEPSP-area was greater in kindled compared to control group only in ventral hippocampus. PTZ kindled slices showed impaired short-term facilitation and the paired-pulse index was reduced only at dorsal hippocampal slices. Kindling had no significant effect on paired-pulse ratio in ventral hippocampal slices. Our findings indicated that the seizure occurrence affected the neural activity of hippocampus in a regional dependent manner. Although kindling increased fEPSP-area in ventral hippocampus, kindling-induced changes in short-term synaptic plasticity was significant only in dorsal hippocampal slices compared to control group. The difference in the responses of hippocampal dorsal and ventral poles has to be considered in the future researches.

Inflammatory markers as prognosticators of cardiovascular dysfunction in hypothyroid patients

Hypothyroidism is a condition characterized by reduced circulating levels of thyroid hormones, T3 (tri-iodothyronine) and T4 (tetra-iodothyronine) which are produced by the thyroid gland, and increased levels of Thyroid Stimulating Hormone (TSH) from the anterior pituitary (1). The cardiovascular system is among the main targets of thyroid hormones (2), therefore, most descriptive signs and symptoms of thyroid disorders are due to their effects on the cardiovascular system (3). Direct actions of altered thyroid hormones on heart and indirect impacts through inflammatory markers, such as C-reactive protein (CRP), Interleukin-6 (IL-6) and Homocysteine (Hcy), are of great health concern. Particularly, CRP is a renowned biomarker to measure cardiovascular risks in both healthy as well as diseased subjects (4). Moreover, IL-6 is a chief mediator of tissue injury and infection, perpetuating lymphocyte infiltration in thyroid, manifesting its inflammation (5). Additionally, Hcy, having an atherogenic nature, stimulates inflammatory chemokine production and induces oxidative stress by lowering serum anti-oxidants (6). Hence, inflammatory markers may reveal the mechanism of disease progression, and can be used as a possible tool for predicting atherosclerosis and cardiovascular events (7). The aim of the present study was to assess the risk of cardiovascular dysfunctions in hypothyroid patients through predictive inflammatory markers.

GLP-1, a powerful physiological incretin: an update

Food intake, especially carbohydrates, release incretin, which is an endocrine transmitter. Among the various endocrine modulators, Glucagon-like peptide 1 (GLP-1) is more effective in stimulating the release of insulin and more powerful regulator of physiological functions. Mainly (GLP-1) receptors are expressed in lungs, α and β cells of pancreatic islets and the nervous system. Peripheral tissues, gastrointestinal tract and extra pancreatic tissues i.e., vascular smooth muscle, kidney and heart, also contain high affinity receptors for GLP-1. The aim of this systematic review was to gather the available published evidence of the functions performed by GLP-1 through the activation of its receptor in various organs. This review suggest that GLP-1 receptor signaling helps prevent beta cell apoptosis and conserve function and morphology of human islet. The effect of GLP-1 signaling in weight loss in diabetic patients was proved by previous studies. The long term use of GLP-1 receptor agonists reduces cardiovascular and renal complications in diabetic patients. Significant evidence was found in previous literature for its effect on pancreatic secretions. The secretions of many enzymes and hormones, such as trypsin, lipase and glucagon, inhibited significantly while the increase in levels of insulin and somatostatin was reported in many studies. GLP-1 has a prominent role in cardiac functioning and increases the heart rate considerably. Based on the vast impact of GLP-1 on physiological functions, many GLP-1 receptor agonists can be made that can increase the healthy life span.