Calcitonin gene-related peptide (CGRP) released from perivascular sensory nerves plays a role in the regulation of vascular tone. Indeed, electrical stimulation of the perivascular sensory out-flow in pithed rats produces vasodepressor responses, which are mainly mediated by CGRP release. This study investigated the potential role of dopamine D 1 -like and D 2 -like receptors in the inhibition of these vasodepressor responses. For this purpose, male Wistar pithed rats (pre-treated i.v. with 25 mg/kg gallamine and 2 mg/kg min. hexamethonium) received i.v. continuous infusions of methoxamine (20 lg/kg min.) followed by physiological saline (0.02 ml/min.), the D 1 -like receptor agonist SKF-38393 (0.1-1 lg/kg min.) or the D 2 -like receptor agonist quinpirole (0.03-10 lg/kg min.). Under these conditions, electrical stimulation (0.56-5.6 Hz; 50 V and 2 ms) of the thoracic spinal cord (T 9 -T 12 ) resulted in frequency-dependent vasodepressor responses which were (i) unchanged during the infusions of saline or SKF-38393 and (ii) inhibited during the infusions of quinpirole (except at 0.03 lg/kg min.). Moreover, the inhibition induced by 0.1 lg/kg min. quinpirole (which failed to inhibit the vasodepressor responses elicited by i.v. bolus injections of exogenous a-CGRP; 0.1-1 lg/kg) was (i) unaltered after i.v. treatment with 1 ml/kg of either saline or 5% ascorbic acid and (ii) abolished after 300 lg/kg (i.v.) of the D 2 -like receptor antagonists haloperidol or raclopride. These doses of antagonists (enough to completely block D 2 -like receptors) essentially failed to modify per se the electrically induced vasodepressor responses. In conclusion, our results suggest that quinpirole-induced inhibition of the vasodepressor sensory CGRPergic out-flow is mainly mediated by pre-junctional D 2 -like receptors.It has been widely documented that dopamine regulates a broad range of physiological functions (including cardiovascular homeostasis), and it contributes to blood pressure control due to its peripheral action on the kidney, adrenal glands and vascular tone [1][2][3][4][5][6][7]. With the conjunction of structural, transductional and operational (pharmacological) criteria, dopamine receptors can be classified into Regarding resistance blood vessels, these are mainly innervated by sympathetic [8] and primary sensory [9] nerves which modulate the vascular tone. The perivascular sensory nerves are mainly C-fibres originating from the spinal cord and, upon stimulation, cause a non-adrenergic, non-cholinergic (NANC) vasodilatation via the release of neuropeptides, primarily calcitonin gene-related peptide (CGRP) [9]. CGRP is predominantly located in sensory neurons (including perivascular nerves), where it is colocalized with other neuropeptides, such as substance P and neurokinin A [10].Interestingly, Taguchi et al.[9] have shown that electrical stimulation of the thoracic (T 9 -T 12 ) spinal cord in pithed rats receiving i.v. infusions of hexamethonium and methoxamine caused vasodepressor responses, which are ma...