Subthreshold Doses of Inflammatory Mediators potentiate one another to Elicit Reflex Cardiorespiratory Responses in Anesthetized Rats

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BACKGROUND: Reflex cardio-vascular and respiratory (CVR) alterations evoked by intra-arterial instillation of nociceptive agents are termed vasosensory reflexes. Such responses elicited by optimal doses of inflammatory mediators have been described in our earlier work.

OBJECTIVE: The present study was designed to evaluate the interactions between subthreshold doses of inflammatory mediators on perivascular nociceptive afferents in urethane anesthetized rats.

METHODS: Healthy male adult rats (Charles-Foster strain) were anesthetized with an intraperitoneal injection of urethane. After anesthesia, the right femoral artery was cannulated. Respiratory movements, blood pressure, and electrocardiogram were recorded. The interactions between subthreshold doses of algogens in the elicitation of vasosensory reflex responses were studied by instillation of bradykinin (1 nM) and histamine (100 µM) into the femoral artery one after the other, in either temporal combination in separate groups of rats. The CVR responses obtained in these groups were then compared with the responses produced by 100 µM histamine and 1 nM bradykinin in saline-pretreated groups, which served as control.

RESULTS: Subthreshold doses of histamine elicited transient tachypnoeic, hyperventilatory, hypotensive, and bradycardiac responses, in rats pretreated with subthreshold doses of bradykinin [P <0.01, two-sided Dunnett's test] but not in saline pretreated groups [P >0.05, two-sided Dunnett's test]. Similar responses were elicited by bradykinin after histamine pretreatment compared to the saline-pretreated group. Furthermore, CVR responses produced by histamine in the bradykinin-pretreated group were greater in magnitude as compared to bradykinin-induced responses in the histamine-pretreated group [P <0.05, two-sided Dunnett's test].

CONCLUSION: The present study demonstrates that both bradykinin and histamine potentiate one another in the elicitation of vasosensory reflex responses, and bradykinin is a better potentiator than histamine at the level of perivascular nociceptive afferents in producing reflex CVR changes.

Medienart:

E-Artikel

Erscheinungsjahr:

2023

Erschienen:

2023

Enthalten in:

Zur Gesamtaufnahme - year:2023

Enthalten in:

Cardiovascular & hematological agents in medicinal chemistry - (2023) vom: 07. Apr.

Sprache:

Englisch

Beteiligte Personen:

Revand, Ravindran [VerfasserIn]
Singh, Sanjeev K [VerfasserIn]
Muthu, Madaswamy S [VerfasserIn]

Links:

Volltext

Themen:

Bradykinin
Histamine
Journal Article
Nociception
Potentiation
Sub-threshold
Vasosensory reflexes

Anmerkungen:

Date Revised 10.04.2023

published: Print-Electronic

Citation Status Publisher

doi:

10.2174/1871525721666230407103734

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM355371405