NEUROHUMORAL ACTIVATION IN HEART-FAILURE - ROLE OF PARAVENTRICULAR NUCLEUS

1. A number of neurohumoral processes are activated in heart failure ( HF), including an increase in the plasma concentration of noradrenalin e. 2. Few studies have been performed to examine the role of the centr al nervous system (CNS) in the activation of sympathetic outflow durin g HF. In the present paper we review the limited studies performed to examine the role of the CNS in the activation of sympathetic outflow, with particular emphasis on our recent study that examined the activit y of discrete regions of the brain as assessed by histological localiz ation and photodensitometric quantification of the metabolic enzyme he xokinase during HF. 3. There were significant increases in hexokinase activity in the parvocellular (pPVN) and magnocellular (mPVN) division s of the paraventricular nucleus of the hypothalamus and in the locus coeruleus (LC) in rats with HF. Na changes in hexokinase activity were observed in the median preoptic area, supraoptic nucleus (SON) or pos terior hypothalamus. 4. We conclude that HF is associated with changes in specific areas in the brain and that alterations in the activation of neurons in the pPVN, mPVN and LC are likely to be related to alter ations in vasopressin production, blood volume regulation and sympatho excitation observed in the HF state.