| Full text | |
| Author(s): |
Dantas Rodrigues, Juliano Quintella
[1]
;
Camara, Henrique
[1]
;
da Silva Junior, Edilson Dantas
[1]
;
Godinho, Rosely Oliveira
[1]
;
Jurkiewicz, Aron
[1]
Total Authors: 5
|
| Affiliation: | [1] Univ Fed Sao Paulo, UNIFESP, EPM, Dept Pharmacol, Rua Tres Maio 100, 2 Floor, BR-04044020 Sao Paulo - Brazil
Total Affiliations: 1
|
| Document type: | Journal article |
| Source: | Journal of Cardiovascular Pharmacology; v. 74, n. 6, p. 542-548, DEC 2019. |
| Web of Science Citations: | 0 |
| Abstract | |
Hypertension represents an autonomic dysfunction, characterized by increased sympathetic and decreased parasympathetic cardiovascular tone leading to resting tachycardia. Therefore, studies assessing hypertension-associated changes in isolated cardiac tissues were conducted under electric field stimulation to stimulate the neurons. Herein, we characterize the influence of the autonomic neurotransmitter on the baseline atrial chronotropism of unpaced isolated right atria of normotensive Wistar rats (NWR) and spontaneously hypertensive rats (SHR). Our results revealed a resting bradycardia in tissues from SHR in comparison to NWR. The release of autonomic neurotransmitters, acetylcholine or norepinephrine, still occurs in the electrically unstimulated right atrium, after excision of the sympathetic nerve, which could explain differences in basal heart rate between NWR and SHR. Nicotine and the acetylcholinesterase inhibitor physostigmine reduced the chronotropism of right atria from either NWR or SHR. Conversely, the muscarinic receptor antagonist atropine did not affect the basal chronotropism of tissues from both strains. Furthermore, tyramine increased the chronotropism of NWR and SHR atria indicating availability of the neuronal stocks of noradrenaline. Although the monoamine uptake inhibitor cocaine increased right atrium chronotropism in both strains, the basal heart rate was not affected by the beta-adrenoceptor antagonist propranolol. In summary, after acute section of the sympathetic nerve, autonomic neurotransmitters are still released either in resting conditions or upon pharmacological stimulation of right atria from both strains. Nevertheless, autonomic neurotransmission does not affect resting chronotropism, nor is the responsible for reduced basal heart rate of the isolated right atrium of hypertensive rats. (AU) | |
| FAPESP's process: | 12/22763-3 - Functional, biochemical and molecular study of Purinergic P1 and P2 receptors in atria of Normotensive and Hypertensive Rats |
| Grantee: | Juliano Quintella Dantas Rodrigues |
| Support Opportunities: | Scholarships in Brazil - Doctorate |
| FAPESP's process: | 15/07019-4 - Role of the extracellular cyclic AMP-adenosine pathway in the respiratory and neuromuscular physiology and physiopathology |
| Grantee: | Rosely Oliveira Godinho |
| Support Opportunities: | Regular Research Grants |
| FAPESP's process: | 12/24828-5 - Estudo da modulação da função cardíaca pelos receptores purinérgicos em átrios de ratos Wistar - EPM-1 |
| Grantee: | Henrique Camara |
| Support Opportunities: | Scholarships in Brazil - Scientific Initiation |