Summary
In rats anaesthetised with alphaxalone/alphadolone, electrical stimulation in the dorsal periaqueductal grey matter (PAG) evoked a presser response with tachycardia, vasodilatation in the hindlimb and hyperpnoea: a pattern of response known as the defence reaction. Microinjection of the synaptic excitant, D,L-homocysteic acid (DLH), but not saline, into the ventrolateral PAG at the level of the decussation of the superior cerebellar peduncle (approximately 7.3–8.3 mm caudal to bregma) produced a reduction in the size of the cardiovascular components of the defence reaction evoked by electrical stimulation in the dorsal PAG. Injections of DLH made outside this region had no effect on the defence response. Injection of DLH into the “defence inhibition area” had no effect on the presser response evoked distally in the efferent pathway for the defence reaction, by electrical stimulation in the rostral ventrolateral medulla (RVLM). Activation of neurones in a restricted portion of the caudal ventrolateral PAG appears to modulate activity in the descending pathway for the defence response evoked from the dorsal PAG. It is argued that the inhibitory interaction probably occurs at the level of synapses in the RVLM.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Abrahams VC, Hilton SM, Zbrozyna AW (1960) Active muscle vasodilatation produced by stimulation in the brainstem: its significance for the defence reaction. J Physiol 154: 491–513
Andrezik JA, Chan-Palay V, Palay SL (1981) The nucleus paragigantocellularis lateralis in the rat: demonstration of afferents by retrograde transport of horseradish peroxidase. Anat Embryol 161: 373–390
Bandler R, Carrive P, Zhang SP (1991) Integration of somatic and autonomie reactions within the midbrain periaqueductal grey: viscerotopic, somatotopic and functional organisation. Progr Brain Res 87: 269–305
Bolles RC, Fanselow MS (1989) A perceptual-defensive-recuperative model of fear and pain. Behav Brain Sci 3: 291–323
Carrive P, Bandler R (1991) Viscerotopic organisation of neurones subserving hypotensive reactions within the midbrain periaqueductal grey: a correlative functional and anatomical study. Brain Res 541: 206–215
Carrive P, Dampney RAL, Bandler R (1987) Excitation of neurones in restricted portion of the midbrain periaqueductal grey matter elicits both behavioural and cardiovascular components of the defence reaction in the unanaesthetised decerebrate cat. Neurosci Lett 81: 273–278
Carrive P, Bandler R, Dampney RAL (1988) Anatomical evidence that hypertension associated with the defence reaction in the cat is mediated by a direct projection from a restricted portion of the midbrain periaqueductal grey to the subretrofacial nucleus of the medulla. Brain Res 460: 339–345
Dennis SG, Choiniere M, Melzack R (1980) Stimulation-produced analgesia in rats: assessment by two pain tests and correlation with self-stimulation. Exp Neurol 68: 295–309
Hilton SM (1982) The defence-arousal system and its relevance for circulatory and respiratory control. J Exp Biol 100: 159–174
Hilton SM, Redfern WS (1986) A search for brainstem cell groups integrating the defence reaction in the rat. J Physiol 387: 213–228
Huangfu DH, Li P (1985) The inhibitory effect of the deep peroneal nerve inputs on defence reaction elicited by brainstem stimulation. Chin J Physiol Sci 1: 176–184
Huangfu DH, Li P (1987) The role of nucleus arcuatus in the inhibitory effect of deep peroneal nerve inputs on the defence reaction. Chin J Physiol Sci 3: 37–46
Li P, Lovick TA (1985) Excitatory projection from hypothalamic and midbrain defence areas to nucleus paragigantocellularis lateralis in the rat. Exp Neurol 89: 543–553
Liebman JM, Mayer DJ, Liebeskind JC (1973) Self-stimulation loci in the midbrain central gray matter of the rat. Behav Biol 9: 299–316
Lovick TA (1986) Projections from brainstem nuclei to nucleus paragigantocellularis lateralis in the cat. J Autonomic Nerv Syst 16: 1–11
Lovick TA (1988) Convergent afferent inputs onto neurones in nucleus paragigantocellularis lateralis in the cat. Brain Res 456: 483–487
Lovick TA (1990) Stimulation in the ventrolateral periaqueductal grey matter modulates cardiovascular responses evoked from the midbrain defence area in anaesthetised rats. J Physiol 426: 80P
Lovick TA (1991a) Central nervous integration of pain and autonomic function. News Physiol Sci 6: 82–86
Lovick TA (1991b) Inhibitory influence from the ventrolateral periaqueductal grey matter on rostral ventrolateral medullospinal neurones in anaesthetised rats. J Physiol 438: 82P
Lovick TA, Smith PR, Hilton SM (1984) Spinally-projecting neurones near the ventral surface of the medulla in the cat. J Autonom Nerv Syst 11: 27–33
Lovick TA, West DC, Wolstencroft JH (1978) Responses of raphespinal and other raphe neurones to stimulation of the periaqueductal grey matter in the cat. Neurosci Lett 8: 45–49
Mancia G, Baccelli G, Zanchetti A (1974) Regulation of renal circulation during behavioural changes in the cat. Am J Physiol 227: 536–542
Nicholas AP, Hancock MB (1990) Evidence for projections from the rostral medullary raphe onto medullary catecholamine neurones in the rat. Neurosci Lett 108: 22–28
Paxinos G, Watson C (1982) The rat brain in stereotaxic coordinates. Academic Press, New York
Piper RD, Goadsby PJ (1985) Pressor response to electrical and chemical stimulation of nucleus raphe dorsalis in the cat. Stroke 16: 307–312
Yardley CP, Hilton SM (1986) The hypothalamic and brainstem areas from which the cardiovascular and behavioural components of the defense reaction are elicited in the rat. J Autonom Nerv Syst 15: 227–244
Zhang SP, Bandler R, Carrive P (1990) Flight and immobility evoked by excitatory amino acid microinjection within distinct parts of the subtentorial midbrain periaqueductal gray of the cat. Brain Res 520: 73–82
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Lovick, T.A. Inhibitory modulation of the cardiovascular defence response by the ventrolateral periaqueductal grey matter in rats. Exp Brain Res 89, 133–139 (1992). https://doi.org/10.1007/BF00229010
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00229010