title: Neuromolecular basis of impaired conditioned taste aversion acquisition in valproate-induced rat model of autism spectrum disorder

authors: Pal, Tapasya

subjects: autism

abstract: Background/Objectives: Autism spectrum disorder (ASD), defined by social, behavioral, and cognitive anomalies, is also associated with dysregulated appetite. ASD individuals, often described as “picky eaters”, exhibit restricted dietary preferences and a pronounced avoidance of novel foods. This suggests that the perceived safety of specific tastants may be a crucial determinant of dietary acceptance in ASD. Here, we explore the hypothesis that conditioned taste aversion (CTA), a learned avoidance of foods whose intake promotes sickness, is exacerbated in ASD. Methods: We assessed the magnitude of a lithium chloride (LiCl)-induced CTA in the valproic acid (VPA) rat model of autism versus in healthy control rats. We also examined the effect of a standard 3 mEq LiCl dose on transcript and neuronal activation changes in brain circuits mediating feeding behavior and associative learning. Results: Surprisingly, we found that while 3 mEq LiCl induced CTA in healthy controls, even the 6 mEq dose was ineffective in generating aversion in VPA rats. LiCl at 3 mEq affected c-Fos immunoreactivity in the hypothalamus and amygdala in controls, whereas in VPA rats it did not produce any c-Fos changes. Gene expression analysis of feeding-related genes (AgRP, NPY, OXT) and those involved in regulating stress and anxiety (DOR and MC3R) were differentially regulated in the VPA rats. Interestingly, transcripts for COMT1, AgRP, OXT, and MC3R were downregulated in saline-treated VPA rats compared to saline-treated controls. Conclusions: We conclude that VPA rats show blunted CTA responsiveness, which is reflected by a differential impact of LiCl on circuits that promote the acquisition of CTA in healthy versus autistic individuals.

text: Neuromolecular basis of impaired conditioned taste aversion acquisition in valproate-induced rat model of autism spectrum disorder Background/Objectives: Autism spectrum disorder (ASD), defined by social, behavioral, and cognitive anomalies, is also associated with dysregulated appetite. ASD individuals, often described as “picky eaters”, exhibit restricted dietary preferences and a pronounced avoidance of novel foods. This suggests that the perceived safety of specific tastants may be a crucial determinant of dietary acceptance in ASD. Here, we explore the hypothesis that conditioned taste aversion (CTA), a learned avoidance of foods whose intake promotes sickness, is exacerbated in ASD. Methods: We assessed the magnitude of a lithium chloride (LiCl)-induced CTA in the valproic acid (VPA) rat model of autism versus in healthy control rats. We also examined the effect of a standard 3 mEq LiCl dose on transcript and neuronal activation changes in brain circuits mediating feeding behavior and associative learning. Results: Surprisingly, we found that while 3 mEq LiCl induced CTA in healthy controls, even the 6 mEq dose was ineffective in generating aversion in VPA rats. LiCl at 3 mEq affected c-Fos immunoreactivity in the hypothalamus and amygdala in controls, whereas in VPA rats it did not produce any c-Fos changes. Gene expression analysis of feeding-related genes (AgRP, NPY, OXT) and those involved in regulating stress and anxiety (DOR and MC3R) were differentially regulated in the VPA rats. Interestingly, transcripts for COMT1, AgRP, OXT, and MC3R were downregulated in saline-treated VPA rats compared to saline-treated controls. Conclusions: We conclude that VPA rats show blunted CTA responsiveness, which is reflected by a differential impact of LiCl on circuits that promote the acquisition of CTA in healthy versus autistic individuals.

year: 2025

title: A water quality model for Lake Tikitapu

authors: McBride, Chris G.

abstract: Lake Tikitapu is a small lake in the Rotorua Te Arawa Lakes region which is extensively used for recreation and sporting events, and is of cultural significance to Iwi (Te Arawa). It is an attractive and popular lake with oligotrophic-mesotrophic water quality. Tikitapu's target Trophic Level Index (TLI; Burns 1999) is 2.7, whereas a TLI of approximately 3 was observed between 2000 and 2010. An Action Plan has been established for Lake Tikitapu (BoPRC 2011) and the proposed actions have now been completed (as at 2015), including the reticulation of the lakeside wastewater systems.
This report describes the establishment of a one-dimensional hydrodynamic-ecological computer water quality model (DYRESM-CAEDYM) for Lake Tikitapu. The modelling process includes calculations for catchment and lake water balances, as well as estimation of nutrient loads to the lake. The simulation period spans from 2001 to 2010. The model has been calibrated and validated, and model performance is acceptable relative to other DYRESM-CAEDYM lake applications documented in the literature.
The established model can be used for simulating scenarios of lake management actions, and can be considered a 'decision support tool'. Initial simulations are presented for increased diffusion of silica from lake sediments (C. Hendy, pers. comm.), and for reticulation of lakeside wastewater systems. Septic systems comprise a large fraction of estimated annual nutrient loads, particularly for phosphorus. As such, simulation of the removal of septic tank nutrient loads indicated that this action alone may be sufficient to meet the TLI target for the lake.

text: A water quality model for Lake Tikitapu Lake Tikitapu is a small lake in the Rotorua Te Arawa Lakes region which is extensively used for recreation and sporting events, and is of cultural significance to Iwi (Te Arawa). It is an attractive and popular lake with oligotrophic-mesotrophic water quality. Tikitapu's target Trophic Level Index (TLI; Burns 1999) is 2.7, whereas a TLI of approximately 3 was observed between 2000 and 2010. An Action Plan has been established for Lake Tikitapu (BoPRC 2011) and the proposed actions have now been completed (as at 2015), including the reticulation of the lakeside wastewater systems.
This report describes the establishment of a one-dimensional hydrodynamic-ecological computer water quality model (DYRESM-CAEDYM) for Lake Tikitapu. The modelling process includes calculations for catchment and lake water balances, as well as estimation of nutrient loads to the lake. The simulation period spans from 2001 to 2010. The model has been calibrated and validated, and model performance is acceptable relative to other DYRESM-CAEDYM lake applications documented in the literature.
The established model can be used for simulating scenarios of lake management actions, and can be considered a 'decision support tool'. Initial simulations are presented for increased diffusion of silica from lake sediments (C. Hendy, pers. comm.), and for reticulation of lakeside wastewater systems. Septic systems comprise a large fraction of estimated annual nutrient loads, particularly for phosphorus. As such, simulation of the removal of septic tank nutrient loads indicated that this action alone may be sufficient to meet the TLI target for the lake.

year: 2014

title: Implications and opportunities for Maori land in the Rotorua catchment

authors: Tahana, Arapeta

abstract: Arapeta is the Portfolio Manager, Waiariki Region, at Te Tumu Paeroa. He works with Maori land owners to enable them to achieve higher aspirations for their land and assets. He also collaborates with a wide range of other people and organisations, from owners in Māori land blocks, to government agencies, private sector companies and experts in many fields to find innovative and pragmatic solutions to the challenges of growing Māori. He is an elected member on the Māori Advisory Committee to RDC working to develop a meaningful partnership between Te Arawa and the Council.

text: Implications and opportunities for Maori land in the Rotorua catchment Arapeta is the Portfolio Manager, Waiariki Region, at Te Tumu Paeroa. He works with Maori land owners to enable them to achieve higher aspirations for their land and assets. He also collaborates with a wide range of other people and organisations, from owners in Māori land blocks, to government agencies, private sector companies and experts in many fields to find innovative and pragmatic solutions to the challenges of growing Māori. He is an elected member on the Māori Advisory Committee to RDC working to develop a meaningful partnership between Te Arawa and the Council.

year: 2013