The role of purinergic P2Y12 and P2Y13 receptors in ADPβS-induced inhibition of the cardioaccelerator sympathetic drive in pithed rats

Hemodynamic responses to endothelin (ET-1) were studied in hindquarters of anesthetized rats and also in isolated buffer-perfused hindquarters of pithed rats. ET-1 (10-100 pmol ia) produced brief dose-related increases in hindquarter blood flow. Acetylcholine (ACh. 0.3-1 micrograms ia) produced similar vasodilator responses. Hemodynamic responses elicited by either ET-1 or ACh were not significantly altered by pretreatment with indomethacin. ET-1 produced dose-dependent increases in skeletal muscle microvascular perfusion, whereas ET-1 had no effect on cutaneous microvascular perfusion, suggesting that vasodilation in the skeletal muscle of the hindlimb contributes to the increase in hindquarter blood flow induced by ET-1. Hemodynamic effects of ET-1 and ACh were studied in the isolated in situ buffer-perfused hindquarters of pithed rats. ET-1 (0.01-300 pmol ia) produced only dose-dependent increases in hindquarter perfusion pressure under basal conditions or when the vascular preparation was precontracted with methoxamine. ET-1 induced vasorelaxation was not observed. ACh (3 microgram ia) produced a 64% reduction in hindquarter perfusion pressure; indicative of endothelium-dependent relaxation. ET-3 (0.1-300 pmol) produced only dose-dependent increases in hindquarter perfusion pressure. When hemodynamic effects of ET-1 were studied under conditions of constant pressure, results were similar to those obtained under constant flow. This study demonstrates that in the rat hindquarters endothelium-derived relaxing factors and prostanoids do not appear to be mediators of endothelin-induced vasodilation.(ABSTRACT TRUNCATED AT 250 WORDS)

Download Full-text

The vasodepressor effect of androgens in pithed rats: potential role of calcium channels

Steroids ◽

10.1016/s0039-128x(02)00061-2 ◽

2002 ◽

Vol 67 (13-14) ◽

pp. 1021-1028 ◽

Cited By ~ 13

Author(s):

Mercedes Perusquı́a ◽

Carlos M Villalón

Keyword(s):

Calcium Channels ◽

Potential Role ◽

Pithed Rats

Download Full-text

Suppression of Non-Esterified Fatty Acids and Triacylglycerol in Experimental Animals by the Adenosine Analogue GR79236

Clinical Science ◽

10.1042/cs0840663 ◽

1993 ◽

Vol 84 (6) ◽

pp. 663-669 ◽

Cited By ~ 28

Author(s):

P. Strong ◽

R. Anderson ◽

J. Coates ◽

F. Elus ◽

B. Evans ◽

...

Keyword(s):

Fatty Acids ◽

Oral Administration ◽

Dose Range ◽

Blood Concentrations ◽

Esterified Fatty Acids ◽

Pithed Rats ◽

A1 Receptor ◽

Isolated Adipocytes ◽

Dose Dependent

1. This is the first description of the metabolic activity of a novel adenosine A1-receptor agonist, GR79236. GR79236 inhibited catecholamine-induced lipolysis in human, rat and dog isolated adipocytes. 2. Oral administration of GR79236 (0.1-10 mg/kg) to fed rats induced minimal changes in the plasma concentration of non-esterified fatty acids and in the blood concentrations of glucose and lactate. 3. Intravenous infusion of GR79236 to fasted pithed rats, or oral administration of GR79236 to fasted conscious rats and dogs, produced time- and dose-dependent decreases in the plasma non-esterified fatty acid concentration. In the fasted rats, doses of GR79236 that lowered plasma levels of non-esterified fatty acids also produced hypotriglyceridaemia and anti-ketotic effects. 4. Only in the pithed rats were acute effects on the plasma glucose and lactate concentrations observed. Hypoglycaemia and hyperlactataemia occurred over the dose range studied (1 × 10−11-1 × 10−8 mol min−1 kg−1). 5. This profile of activity suggests that compounds such as GR79236 might be agents which can be used to define the role of excessive lipolysis in experimental (and human) pathophysiology.

Download Full-text

The role of α1- and α2-adrenoceptor subtypes in the vasopressor responses induced by dihydroergotamine in ritanserin-pretreated pithed rats

The Journal of Headache and Pain ◽

10.1186/s10194-017-0812-4 ◽

2017 ◽

Vol 18 (1) ◽

Cited By ~ 2

Author(s):

Eduardo Rivera-Mancilla ◽

Victor H. Avilés-Rosas ◽

Guadalupe Manrique-Maldonado ◽

Alain H. Altamirano-Espinoza ◽

Belinda Villanueva-Castillo ◽

...

Keyword(s):

Α2 Adrenoceptor ◽

Pithed Rats

Download Full-text

Fluoxetine oral treatment discloses 5-HT1D receptor as vagoinhibitor of the cardiac cholinergic neurotransmission in rat

Canadian Journal of Physiology and Pharmacology ◽

10.1139/cjpp-2018-0390 ◽

2019 ◽

Vol 97 (2) ◽

pp. 90-98 ◽

Cited By ~ 1

Author(s):

Cristina López ◽

Miriam Gómez-Roso ◽

José Ángel García-Pedraza ◽

María Luisa Martín ◽

Asunción Morán ◽

...

Keyword(s):

Vagal Stimulation ◽

Oral Treatment ◽

Inhibitory Effect ◽

Control Group ◽

Water Control ◽

Fluoxetine Treatment ◽

Pithed Rats ◽

Cardiac Regulation ◽

Stimulation Of

Although depression and cardiovascular diseases are related, the role of antidepressants such as fluoxetine (increasing serotonin levels) within cardiac regulation remains unclear. We aimed to determine whether fluoxetine modifies the pharmacological profile of serotonergic influence on vagal cardiac outflow. Rats were treated with fluoxetine (10 mg/kg per day; p.o.) for 14 days or equivalent volumes of drinking water (control group); then, they were pithed and prepared for vagal stimulation. Bradycardic responses were obtained by electrical stimulation of the vagal fibers (3, 6, and 9 Hz) or i.v. acetylcholine (ACh; 1, 5, and 10 μg/kg). The i.v. administration of 5-hydroxytryptamine (5-HT; 10 and 50 μg/kg) inhibited the vagally induced bradycardia. 5-CT (5-HT1/7 agonist) and L-694,247 (5-HT1D agonist) mimicked the serotonin inhibitory effect while α-methyl-5-HT (5-HT2 agonist) was devoid of any action. SB269970 (5-HT7 antagonist) did not abolish 5-CT inhibitory action on the electrically induced bradycardia. Pretreatment with LY310762 (5-HT1D antagonist) blocked the effects induced by L-694,247 and 5-CT. 5-HT and 5-CT failed to modify the bradycardia induced by exogenous ACh. Our outcomes suggest that fluoxetine treatment modifies 5-HT modulation on heart parasympathetic neurotransmission in rats, evoking inhibition of the bradycardia via prejunctional 5-HT1D in pithed rats.

Download Full-text